import java.util.*; public class Main { public static final int MOD998 = 998244353; public static final int MOD100 = 1000000007; public static void main(String[] args) throws Exception { ContestScanner sc = new ContestScanner(); ContestPrinter cp = new ContestPrinter(); int N = sc.nextInt(); int M = sc.nextInt(); int[][] arr = sc.nextIntArrayMulti(M, 2); for (int i = 0; i < M; i++) { arr[0][i]--; arr[1][i]--; } int[][] graph = GraphBuilder.makeGraph(N, M, arr[0], arr[1], true); LinkedList queue = new LinkedList<>(); int[] visited = new int[N]; Arrays.fill(visited, -1); boolean ok = true; for (int i = 0; i < N; i++) { if (visited[i] == -1) { visited[i] = 0; queue.add(i); while (!queue.isEmpty()) { int v = queue.poll(); for (int x : graph[v]) { if (visited[x] == visited[v]) { ok = false; } if (visited[x] == -1) { queue.add(x); } visited[x] = 1 - visited[v]; } } } } cp.println(ok ? "Yes" : "No"); cp.close(); } ////////////////// // My Library // ////////////////// public static class SlopeTrick { private PriorityQueue lq = new PriorityQueue<>(Comparator.reverseOrder()); private PriorityQueue rq = new PriorityQueue<>(); private long lshift = 0; private long rshift = 0; private long min = 0; public long getMin() { return min; } public long get(long x) { long val = min; for (long l : lq) { if (l - x > 0) { val += l - x; } } for (long r : rq) { if (x - r > 0) { val += x - r; } } return val; } public long getMinPosLeft() { return lq.isEmpty() ? Long.MIN_VALUE : lq.peek() + lshift; } public long getMinPosRight() { return rq.isEmpty() ? Long.MAX_VALUE : rq.peek() + rshift; } public void addConst(long a) { min += a; } public void addSlopeRight(long a) { if (!lq.isEmpty() && lq.peek() + lshift > a) { min += lq.peek() + lshift - a; lq.add(a - lshift); rq.add(lq.poll() + lshift - rshift); } else { rq.add(a - rshift); } } public void addSlopeLeft(long a) { if (!rq.isEmpty() && rq.peek() < a) { min += a - rq.peek() - rshift; rq.add(a - rshift); lq.add(rq.poll() + rshift - lshift); } else { lq.add(a - lshift); } } public void addAbs(long a) { addSlopeLeft(a); addSlopeRight(a); } public void shift(long a) { lshift += a; rshift += a; } public void slideLeft(long a) { lshift += a; } public void slideRight(long a) { rshift += a; } public void clearLeft() { lq.clear(); } public void clearRight() { rq.clear(); } public void clearMin() { min = 0; } } public static int zeroOneBFS(int[][][] weighted_graph, int start, int goal) { int[] dist = new int[weighted_graph.length]; Arrays.fill(dist, Integer.MAX_VALUE); dist[start] = 0; LinkedList queue = new LinkedList<>(); queue.add(start); while (!queue.isEmpty()) { int now = queue.poll(); if (now == goal) { return dist[goal]; } for (int[] info : weighted_graph[now]) { if (dist[info[0]] > dist[now] + info[1]) { dist[info[0]] = dist[now] + info[1]; if (info[1] == 0) { queue.addFirst(info[0]); } else { queue.addLast(info[0]); } } } } return -1; } public static int[] zeroOneBFSAll(int[][][] weighted_graph, int start) { int[] dist = new int[weighted_graph.length]; Arrays.fill(dist, Integer.MAX_VALUE); dist[start] = 0; LinkedList queue = new LinkedList<>(); queue.add(start); while (!queue.isEmpty()) { int now = queue.poll(); for (int[] info : weighted_graph[now]) { if (dist[info[0]] > dist[now] + info[1]) { dist[info[0]] = dist[now] + info[1]; if (info[1] == 0) { queue.addFirst(info[0]); } else { queue.addLast(info[0]); } } } } return dist; } static int[][] scanGraphOneIndexed(ContestScanner sc, int node, int edge, boolean undirected) { int[][] arr = sc.nextIntArrayMulti(edge, 2); for (int n = 0; n < edge; n++) { arr[0][n]--; arr[1][n]--; } return GraphBuilder.makeGraph(node, edge, arr[0], arr[1], undirected); } static int[][][] scanWeightedGraphOneIndexed(ContestScanner sc, int node, int edge, boolean undirected) { int[][] arr = sc.nextIntArrayMulti(edge, 3); for (int n = 0; n < edge; n++) { arr[0][n]--; arr[1][n]--; } return GraphBuilder.makeGraphWithWeight(node, edge, arr[0], arr[1], arr[2], undirected); } static class EdgeData { private int capacity; private int[] from, to, weight; private int p = 0; private boolean weighted; public EdgeData(boolean weighted) { this(weighted, 500000); } public EdgeData(boolean weighted, int initial_capacity) { capacity = initial_capacity; from = new int[capacity]; to = new int[capacity]; weight = new int[capacity]; this.weighted = weighted; } public void addEdge(int u, int v) { if (weighted) { System.err.println("The graph is weighted!"); return; } if (p == capacity) { int[] newfrom = new int[capacity * 2]; int[] newto = new int[capacity * 2]; System.arraycopy(from, 0, newfrom, 0, capacity); System.arraycopy(to, 0, newto, 0, capacity); capacity *= 2; from = newfrom; to = newto; } from[p] = u; to[p] = v; p++; } public void addEdge(int u, int v, int w) { if (!weighted) { System.err.println("The graph is NOT weighted!"); return; } if (p == capacity) { int[] newfrom = new int[capacity * 2]; int[] newto = new int[capacity * 2]; int[] newweight = new int[capacity * 2]; System.arraycopy(from, 0, newfrom, 0, capacity); System.arraycopy(to, 0, newto, 0, capacity); System.arraycopy(weight, 0, newweight, 0, capacity); capacity *= 2; from = newfrom; to = newto; weight = newweight; } from[p] = u; to[p] = v; weight[p] = w; p++; } public int[] getFrom() { int[] result = new int[p]; System.arraycopy(from, 0, result, 0, p); return result; } public int[] getTo() { int[] result = new int[p]; System.arraycopy(to, 0, result, 0, p); return result; } public int[] getWeight() { int[] result = new int[p]; System.arraycopy(weight, 0, result, 0, p); return result; } public int size() { return p; } } //////////////////////////////// // Atcoder Library for Java // //////////////////////////////// static class MathLib { private static long safe_mod(long x, long m) { x %= m; if (x < 0) x += m; return x; } private static long[] inv_gcd(long a, long b) { a = safe_mod(a, b); if (a == 0) return new long[] { b, 0 }; long s = b, t = a; long m0 = 0, m1 = 1; while (t > 0) { long u = s / t; s -= t * u; m0 -= m1 * u; long tmp = s; s = t; t = tmp; tmp = m0; m0 = m1; m1 = tmp; } if (m0 < 0) m0 += b / s; return new long[] { s, m0 }; } public static long gcd(long a, long b) { a = java.lang.Math.abs(a); b = java.lang.Math.abs(b); if (a == 0) { return b; } else if (b == 0) { return a; } return inv_gcd(a, b)[0]; } public static long lcm(long a, long b) { a = java.lang.Math.abs(a); b = java.lang.Math.abs(b); return a / gcd(a, b) * b; } public static long pow_mod(long x, long n, int m) { assert n >= 0; assert m >= 1; if (m == 1) return 0L; x = safe_mod(x, m); long ans = 1L; while (n > 0) { if ((n & 1) == 1) ans = (ans * x) % m; x = (x * x) % m; n >>>= 1; } return ans; } public static long[] crt(long[] r, long[] m) { assert (r.length == m.length); int n = r.length; long r0 = 0, m0 = 1; for (int i = 0; i < n; i++) { assert (1 <= m[i]); long r1 = safe_mod(r[i], m[i]), m1 = m[i]; if (m0 < m1) { long tmp = r0; r0 = r1; r1 = tmp; tmp = m0; m0 = m1; m1 = tmp; } if (m0 % m1 == 0) { if (r0 % m1 != r1) return new long[] { 0, 0 }; continue; } long[] ig = inv_gcd(m0, m1); long g = ig[0], im = ig[1]; long u1 = m1 / g; if ((r1 - r0) % g != 0) return new long[] { 0, 0 }; long x = (r1 - r0) / g % u1 * im % u1; r0 += x * m0; m0 *= u1; if (r0 < 0) r0 += m0; // System.err.printf("%d %d\n", r0, m0); } return new long[] { r0, m0 }; } public static long floor_sum(long n, long m, long a, long b) { long ans = 0; if (a >= m) { ans += (n - 1) * n * (a / m) / 2; a %= m; } if (b >= m) { ans += n * (b / m); b %= m; } long y_max = (a * n + b) / m; long x_max = y_max * m - b; if (y_max == 0) return ans; ans += (n - (x_max + a - 1) / a) * y_max; ans += floor_sum(y_max, a, m, (a - x_max % a) % a); return ans; } public static java.util.ArrayList divisors(long n) { java.util.ArrayList divisors = new ArrayList<>(); java.util.ArrayList large = new ArrayList<>(); for (long i = 1; i * i <= n; i++) if (n % i == 0) { divisors.add(i); if (i * i < n) large.add(n / i); } for (int p = large.size() - 1; p >= 0; p--) { divisors.add(large.get(p)); } return divisors; } } static class HashMultiset extends java.util.HashMap { public HashMultiset() { super(); } public HashMultiset(java.util.List list) { super(); for (T e : list) this.addOne(e); } public long count(Object elm) { return getOrDefault(elm, 0L); } public void add(T elm, long amount) { if (!this.containsKey(elm)) put(elm, amount); else replace(elm, get(elm) + amount); if (this.count(elm) == 0) this.remove(elm); } public void addOne(T elm) { this.add(elm, 1); } public void removeOne(T elm) { this.add(elm, -1); } public void removeAll(T elm) { this.add(elm, -this.count(elm)); } public static HashMultiset merge(HashMultiset a, HashMultiset b) { HashMultiset c = new HashMultiset<>(); for (T x : a.keySet()) c.add(x, a.count(x)); for (T y : b.keySet()) c.add(y, b.count(y)); return c; } } static class GraphBuilder { public static int[][] makeGraph(int NumberOfNodes, int NumberOfEdges, int[] from, int[] to, boolean undirected) { int[][] graph = new int[NumberOfNodes][]; int[] outdegree = new int[NumberOfNodes]; for (int i = 0; i < NumberOfEdges; i++) { outdegree[from[i]]++; if (undirected) outdegree[to[i]]++; } for (int i = 0; i < NumberOfNodes; i++) graph[i] = new int[outdegree[i]]; for (int i = 0; i < NumberOfEdges; i++) { graph[from[i]][--outdegree[from[i]]] = to[i]; if (undirected) graph[to[i]][--outdegree[to[i]]] = from[i]; } return graph; } public static int[][][] makeGraphWithWeight(int NumberOfNodes, int NumberOfEdges, int[] from, int[] to, int[] weight, boolean undirected) { int[][][] graph = new int[NumberOfNodes][][]; int[] outdegree = new int[NumberOfNodes]; for (int i = 0; i < NumberOfEdges; i++) { outdegree[from[i]]++; if (undirected) outdegree[to[i]]++; } for (int i = 0; i < NumberOfNodes; i++) graph[i] = new int[outdegree[i]][]; for (int i = 0; i < NumberOfEdges; i++) { graph[from[i]][--outdegree[from[i]]] = new int[] { to[i], weight[i] }; if (undirected) graph[to[i]][--outdegree[to[i]]] = new int[] { from[i], weight[i] }; } return graph; } public static int[][][] makeGraphWithEdgeInfo(int NumberOfNodes, int NumberOfEdges, int[] from, int[] to, boolean undirected) { int[][][] graph = new int[NumberOfNodes][][]; int[] outdegree = new int[NumberOfNodes]; for (int i = 0; i < NumberOfEdges; i++) { outdegree[from[i]]++; if (undirected) outdegree[to[i]]++; } for (int i = 0; i < NumberOfNodes; i++) graph[i] = new int[outdegree[i]][]; for (int i = 0; i < NumberOfEdges; i++) { graph[from[i]][--outdegree[from[i]]] = new int[] { to[i], i, 0 }; if (undirected) graph[to[i]][--outdegree[to[i]]] = new int[] { from[i], i, 1 }; } return graph; } public static int[][][] makeGraphWithWeightAndEdgeInfo(int NumberOfNodes, int NumberOfEdges, int[] from, int[] to, int[] weight, boolean undirected) { int[][][] graph = new int[NumberOfNodes][][]; int[] outdegree = new int[NumberOfNodes]; for (int i = 0; i < NumberOfEdges; i++) { outdegree[from[i]]++; if (undirected) outdegree[to[i]]++; } for (int i = 0; i < NumberOfNodes; i++) graph[i] = new int[outdegree[i]][]; for (int i = 0; i < NumberOfEdges; i++) { graph[from[i]][--outdegree[from[i]]] = new int[] { to[i], weight[i], i, 0 }; if (undirected) graph[to[i]][--outdegree[to[i]]] = new int[] { from[i], weight[i], i, 1 }; } return graph; } } static class DSU { private int n; private int[] parentOrSize; public DSU(int n) { this.n = n; this.parentOrSize = new int[n]; java.util.Arrays.fill(parentOrSize, -1); } int merge(int a, int b) { if (!(0 <= a && a < n)) throw new IndexOutOfBoundsException("a=" + a); if (!(0 <= b && b < n)) throw new IndexOutOfBoundsException("b=" + b); int x = leader(a); int y = leader(b); if (x == y) return x; if (-parentOrSize[x] < -parentOrSize[y]) { int tmp = x; x = y; y = tmp; } parentOrSize[x] += parentOrSize[y]; parentOrSize[y] = x; return x; } boolean same(int a, int b) { if (!(0 <= a && a < n)) throw new IndexOutOfBoundsException("a=" + a); if (!(0 <= b && b < n)) throw new IndexOutOfBoundsException("b=" + b); return leader(a) == leader(b); } int leader(int a) { if (parentOrSize[a] < 0) { return a; } else { parentOrSize[a] = leader(parentOrSize[a]); return parentOrSize[a]; } } int size(int a) { if (!(0 <= a && a < n)) throw new IndexOutOfBoundsException("" + a); return -parentOrSize[leader(a)]; } java.util.ArrayList> groups() { int[] leaderBuf = new int[n]; int[] groupSize = new int[n]; for (int i = 0; i < n; i++) { leaderBuf[i] = leader(i); groupSize[leaderBuf[i]]++; } java.util.ArrayList> result = new java.util.ArrayList<>(n); for (int i = 0; i < n; i++) { result.add(new java.util.ArrayList<>(groupSize[i])); } for (int i = 0; i < n; i++) { result.get(leaderBuf[i]).add(i); } result.removeIf(java.util.ArrayList::isEmpty); return result; } } static class ModIntFactory { private final ModArithmetic ma; private final int mod; private final boolean usesMontgomery; private final ModArithmetic.ModArithmeticMontgomery maMontgomery; private ArrayList factorial; private ArrayList factorial_inversion; public ModIntFactory(int mod) { this.ma = ModArithmetic.of(mod); this.usesMontgomery = ma instanceof ModArithmetic.ModArithmeticMontgomery; this.maMontgomery = usesMontgomery ? (ModArithmetic.ModArithmeticMontgomery) ma : null; this.mod = mod; this.factorial = new ArrayList<>(); this.factorial_inversion = new ArrayList<>(); } public ModInt create(long value) { if ((value %= mod) < 0) value += mod; if (usesMontgomery) { return new ModInt(maMontgomery.generate(value)); } else { return new ModInt((int) value); } } private void prepareFactorial(int max) { factorial.ensureCapacity(max + 1); if (factorial.size() == 0) factorial.add(1); for (int i = factorial.size(); i <= max; i++) { factorial.add(ma.mul(factorial.get(i - 1), i)); } } public ModInt factorial(int i) { prepareFactorial(i); return create(factorial.get(i)); } public ModInt permutation(int n, int r) { if (n < 0 || r < 0 || n < r) return create(0); prepareFactorial(n); if (factorial_inversion.size() > n) { return create(ma.mul(factorial.get(n), factorial_inversion.get(n - r))); } return create(ma.div(factorial.get(n), factorial.get(n - r))); } public ModInt combination(int n, int r) { if (n < 0 || r < 0 || n < r) return create(0); prepareFactorial(n); if (factorial_inversion.size() > n) { return create( ma.mul(factorial.get(n), ma.mul(factorial_inversion.get(n - r), factorial_inversion.get(r)))); } return create(ma.div(factorial.get(n), ma.mul(factorial.get(r), factorial.get(n - r)))); } public void prepareFactorialInv(int max) { prepareFactorial(max); factorial_inversion.ensureCapacity(max + 1); for (int i = factorial_inversion.size(); i <= max; i++) { factorial_inversion.add(ma.inv(factorial.get(i))); } } public int getMod() { return mod; } public class ModInt { private int value; private ModInt(int value) { this.value = value; } public int mod() { return mod; } public int value() { if (ma instanceof ModArithmetic.ModArithmeticMontgomery) { return ((ModArithmetic.ModArithmeticMontgomery) ma).reduce(value); } return value; } public ModInt add(ModInt mi) { return new ModInt(ma.add(value, mi.value)); } public ModInt add(ModInt mi1, ModInt mi2) { return new ModInt(ma.add(value, mi1.value)).addAsg(mi2); } public ModInt add(ModInt mi1, ModInt mi2, ModInt mi3) { return new ModInt(ma.add(value, mi1.value)).addAsg(mi2).addAsg(mi3); } public ModInt add(ModInt mi1, ModInt mi2, ModInt mi3, ModInt mi4) { return new ModInt(ma.add(value, mi1.value)).addAsg(mi2).addAsg(mi3).addAsg(mi4); } public ModInt add(ModInt mi1, ModInt... mis) { ModInt mi = add(mi1); for (ModInt m : mis) mi.addAsg(m); return mi; } public ModInt add(long mi) { return new ModInt(ma.add(value, ma.remainder(mi))); } public ModInt sub(ModInt mi) { return new ModInt(ma.sub(value, mi.value)); } public ModInt sub(long mi) { return new ModInt(ma.sub(value, ma.remainder(mi))); } public ModInt mul(ModInt mi) { return new ModInt(ma.mul(value, mi.value)); } public ModInt mul(ModInt mi1, ModInt mi2) { return new ModInt(ma.mul(value, mi1.value)).mulAsg(mi2); } public ModInt mul(ModInt mi1, ModInt mi2, ModInt mi3) { return new ModInt(ma.mul(value, mi1.value)).mulAsg(mi2).mulAsg(mi3); } public ModInt mul(ModInt mi1, ModInt mi2, ModInt mi3, ModInt mi4) { return new ModInt(ma.mul(value, mi1.value)).mulAsg(mi2).mulAsg(mi3).mulAsg(mi4); } public ModInt mul(ModInt mi1, ModInt... mis) { ModInt mi = mul(mi1); for (ModInt m : mis) mi.mulAsg(m); return mi; } public ModInt mul(long mi) { return new ModInt(ma.mul(value, ma.remainder(mi))); } public ModInt div(ModInt mi) { return new ModInt(ma.div(value, mi.value)); } public ModInt div(long mi) { return new ModInt(ma.div(value, ma.remainder(mi))); } public ModInt inv() { return new ModInt(ma.inv(value)); } public ModInt pow(long b) { return new ModInt(ma.pow(value, b)); } public ModInt addAsg(ModInt mi) { this.value = ma.add(value, mi.value); return this; } public ModInt addAsg(ModInt mi1, ModInt mi2) { return addAsg(mi1).addAsg(mi2); } public ModInt addAsg(ModInt mi1, ModInt mi2, ModInt mi3) { return addAsg(mi1).addAsg(mi2).addAsg(mi3); } public ModInt addAsg(ModInt mi1, ModInt mi2, ModInt mi3, ModInt mi4) { return addAsg(mi1).addAsg(mi2).addAsg(mi3).addAsg(mi4); } public ModInt addAsg(ModInt... mis) { for (ModInt m : mis) addAsg(m); return this; } public ModInt addAsg(long mi) { this.value = ma.add(value, ma.remainder(mi)); return this; } public ModInt subAsg(ModInt mi) { this.value = ma.sub(value, mi.value); return this; } public ModInt subAsg(long mi) { this.value = ma.sub(value, ma.remainder(mi)); return this; } public ModInt mulAsg(ModInt mi) { this.value = ma.mul(value, mi.value); return this; } public ModInt mulAsg(ModInt mi1, ModInt mi2) { return mulAsg(mi1).mulAsg(mi2); } public ModInt mulAsg(ModInt mi1, ModInt mi2, ModInt mi3) { return mulAsg(mi1).mulAsg(mi2).mulAsg(mi3); } public ModInt mulAsg(ModInt mi1, ModInt mi2, ModInt mi3, ModInt mi4) { return mulAsg(mi1).mulAsg(mi2).mulAsg(mi3).mulAsg(mi4); } public ModInt mulAsg(ModInt... mis) { for (ModInt m : mis) mulAsg(m); return this; } public ModInt mulAsg(long mi) { this.value = ma.mul(value, ma.remainder(mi)); return this; } public ModInt divAsg(ModInt mi) { this.value = ma.div(value, mi.value); return this; } public ModInt divAsg(long mi) { this.value = ma.div(value, ma.remainder(mi)); return this; } @Override public String toString() { return String.valueOf(value()); } @Override public boolean equals(Object o) { if (o instanceof ModInt) { ModInt mi = (ModInt) o; return mod() == mi.mod() && value() == mi.value(); } return false; } @Override public int hashCode() { return (1 * 37 + mod()) * 37 + value(); } } private static abstract class ModArithmetic { abstract int mod(); abstract int remainder(long value); abstract int add(int a, int b); abstract int sub(int a, int b); abstract int mul(int a, int b); int div(int a, int b) { return mul(a, inv(b)); } int inv(int a) { int b = mod(); if (b == 1) return 0; long u = 1, v = 0; while (b >= 1) { int t = a / b; a -= t * b; int tmp1 = a; a = b; b = tmp1; u -= t * v; long tmp2 = u; u = v; v = tmp2; } if (a != 1) { throw new ArithmeticException("divide by zero"); } return remainder(u); } int pow(int a, long b) { if (b < 0) throw new ArithmeticException("negative power"); int r = 1; int x = a; while (b > 0) { if ((b & 1) == 1) r = mul(r, x); x = mul(x, x); b >>= 1; } return r; } static ModArithmetic of(int mod) { if (mod <= 0) { throw new IllegalArgumentException(); } else if (mod == 1) { return new ModArithmetic1(); } else if (mod == 2) { return new ModArithmetic2(); } else if (mod == 998244353) { return new ModArithmetic998244353(); } else if (mod == 1000000007) { return new ModArithmetic1000000007(); } else if ((mod & 1) == 1) { return new ModArithmeticMontgomery(mod); } else { return new ModArithmeticBarrett(mod); } } private static final class ModArithmetic1 extends ModArithmetic { int mod() { return 1; } int remainder(long value) { return 0; } int add(int a, int b) { return 0; } int sub(int a, int b) { return 0; } int mul(int a, int b) { return 0; } int pow(int a, long b) { return 0; } } private static final class ModArithmetic2 extends ModArithmetic { int mod() { return 2; } int remainder(long value) { return (int) (value & 1); } int add(int a, int b) { return a ^ b; } int sub(int a, int b) { return a ^ b; } int mul(int a, int b) { return a & b; } } private static final class ModArithmetic998244353 extends ModArithmetic { private final int mod = 998244353; int mod() { return mod; } int remainder(long value) { return (int) ((value %= mod) < 0 ? value + mod : value); } int add(int a, int b) { int res = a + b; return res >= mod ? res - mod : res; } int sub(int a, int b) { int res = a - b; return res < 0 ? res + mod : res; } int mul(int a, int b) { return (int) (((long) a * b) % mod); } } private static final class ModArithmetic1000000007 extends ModArithmetic { private final int mod = 1000000007; int mod() { return mod; } int remainder(long value) { return (int) ((value %= mod) < 0 ? value + mod : value); } int add(int a, int b) { int res = a + b; return res >= mod ? res - mod : res; } int sub(int a, int b) { int res = a - b; return res < 0 ? res + mod : res; } int mul(int a, int b) { return (int) (((long) a * b) % mod); } } private static final class ModArithmeticMontgomery extends ModArithmeticDynamic { private final long negInv; private final long r2; private ModArithmeticMontgomery(int mod) { super(mod); long inv = 0; long s = 1, t = 0; for (int i = 0; i < 32; i++) { if ((t & 1) == 0) { t += mod; inv += s; } t >>= 1; s <<= 1; } long r = (1l << 32) % mod; this.negInv = inv; this.r2 = (r * r) % mod; } private int generate(long x) { return reduce(x * r2); } private int reduce(long x) { x = (x + ((x * negInv) & 0xffff_ffffl) * mod) >>> 32; return (int) (x < mod ? x : x - mod); } @Override int remainder(long value) { return generate((value %= mod) < 0 ? value + mod : value); } @Override int mul(int a, int b) { return reduce((long) a * b); } @Override int inv(int a) { return super.inv(reduce(a)); } @Override int pow(int a, long b) { return generate(super.pow(a, b)); } } private static final class ModArithmeticBarrett extends ModArithmeticDynamic { private static final long mask = 0xffff_ffffl; private final long mh; private final long ml; private ModArithmeticBarrett(int mod) { super(mod); /** * m = floor(2^64/mod) 2^64 = p*mod + q, 2^32 = a*mod + b => (a*mod + b)^2 = * p*mod + q => p = mod*a^2 + 2ab + floor(b^2/mod) */ long a = (1l << 32) / mod; long b = (1l << 32) % mod; long m = a * a * mod + 2 * a * b + (b * b) / mod; mh = m >>> 32; ml = m & mask; } private int reduce(long x) { long z = (x & mask) * ml; z = (x & mask) * mh + (x >>> 32) * ml + (z >>> 32); z = (x >>> 32) * mh + (z >>> 32); x -= z * mod; return (int) (x < mod ? x : x - mod); } @Override int remainder(long value) { return (int) ((value %= mod) < 0 ? value + mod : value); } @Override int mul(int a, int b) { return reduce((long) a * b); } } private static class ModArithmeticDynamic extends ModArithmetic { final int mod; ModArithmeticDynamic(int mod) { this.mod = mod; } int mod() { return mod; } int remainder(long value) { return (int) ((value %= mod) < 0 ? value + mod : value); } int add(int a, int b) { int sum = a + b; return sum >= mod ? sum - mod : sum; } int sub(int a, int b) { int sum = a - b; return sum < 0 ? sum + mod : sum; } int mul(int a, int b) { return (int) (((long) a * b) % mod); } } } } static class ContestScanner { private final java.io.InputStream in; private final byte[] buffer = new byte[1024]; private int ptr = 0; private int buflen = 0; private static final long LONG_MAX_TENTHS = 922337203685477580L; private static final int LONG_MAX_LAST_DIGIT = 7; private static final int LONG_MIN_LAST_DIGIT = 8; public ContestScanner(java.io.InputStream in) { this.in = in; } public ContestScanner() { this(System.in); } private boolean hasNextByte() { if (ptr < buflen) { return true; } else { ptr = 0; try { buflen = in.read(buffer); } catch (java.io.IOException e) { e.printStackTrace(); } if (buflen <= 0) { return false; } } return true; } private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1; } private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126; } public boolean hasNext() { while (hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte(); } public String next() { if (!hasNext()) throw new java.util.NoSuchElementException(); StringBuilder sb = new StringBuilder(); int b = readByte(); while (isPrintableChar(b)) { sb.appendCodePoint(b); b = readByte(); } return sb.toString(); } public long nextLong() { if (!hasNext()) throw new java.util.NoSuchElementException(); long n = 0; boolean minus = false; int b = readByte(); if (b == '-') { minus = true; b = readByte(); } if (b < '0' || '9' < b) { throw new NumberFormatException(); } while (true) { if ('0' <= b && b <= '9') { int digit = b - '0'; if (n >= LONG_MAX_TENTHS) { if (n == LONG_MAX_TENTHS) { if (minus) { if (digit <= LONG_MIN_LAST_DIGIT) { n = -n * 10 - digit; b = readByte(); if (!isPrintableChar(b)) { return n; } else if (b < '0' || '9' < b) { throw new NumberFormatException( String.format("%d%s... is not number", n, Character.toString(b))); } } } else { if (digit <= LONG_MAX_LAST_DIGIT) { n = n * 10 + digit; b = readByte(); if (!isPrintableChar(b)) { return n; } else if (b < '0' || '9' < b) { throw new NumberFormatException( String.format("%d%s... is not number", n, Character.toString(b))); } } } } throw new ArithmeticException( String.format("%s%d%d... overflows long.", minus ? "-" : "", n, digit)); } n = n * 10 + digit; } else if (b == -1 || !isPrintableChar(b)) { return minus ? -n : n; } else { throw new NumberFormatException(); } b = readByte(); } } public int nextInt() { long nl = nextLong(); if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException(); return (int) nl; } public double nextDouble() { return Double.parseDouble(next()); } public long[] nextLongArray(int length) { long[] array = new long[length]; for (int i = 0; i < length; i++) array[i] = this.nextLong(); return array; } public long[] nextLongArray(int length, java.util.function.LongUnaryOperator map) { long[] array = new long[length]; for (int i = 0; i < length; i++) array[i] = map.applyAsLong(this.nextLong()); return array; } public int[] nextIntArray(int length) { int[] array = new int[length]; for (int i = 0; i < length; i++) array[i] = this.nextInt(); return array; } public int[][] nextIntArrayMulti(int length, int width) { int[][] arrays = new int[width][length]; for (int i = 0; i < length; i++) { for (int j = 0; j < width; j++) arrays[j][i] = this.nextInt(); } return arrays; } public int[] nextIntArray(int length, java.util.function.IntUnaryOperator map) { int[] array = new int[length]; for (int i = 0; i < length; i++) array[i] = map.applyAsInt(this.nextInt()); return array; } public double[] nextDoubleArray(int length) { double[] array = new double[length]; for (int i = 0; i < length; i++) array[i] = this.nextDouble(); return array; } public double[] nextDoubleArray(int length, java.util.function.DoubleUnaryOperator map) { double[] array = new double[length]; for (int i = 0; i < length; i++) array[i] = map.applyAsDouble(this.nextDouble()); return array; } public long[][] nextLongMatrix(int height, int width) { long[][] mat = new long[height][width]; for (int h = 0; h < height; h++) for (int w = 0; w < width; w++) { mat[h][w] = this.nextLong(); } return mat; } public int[][] nextIntMatrix(int height, int width) { int[][] mat = new int[height][width]; for (int h = 0; h < height; h++) for (int w = 0; w < width; w++) { mat[h][w] = this.nextInt(); } return mat; } public double[][] nextDoubleMatrix(int height, int width) { double[][] mat = new double[height][width]; for (int h = 0; h < height; h++) for (int w = 0; w < width; w++) { mat[h][w] = this.nextDouble(); } return mat; } public char[][] nextCharMatrix(int height, int width) { char[][] mat = new char[height][width]; for (int h = 0; h < height; h++) { String s = this.next(); for (int w = 0; w < width; w++) { mat[h][w] = s.charAt(w); } } return mat; } } static class ContestPrinter extends java.io.PrintWriter { public ContestPrinter(java.io.PrintStream stream) { super(stream); } public ContestPrinter() { super(System.out); } private static String dtos(double x, int n) { StringBuilder sb = new StringBuilder(); if (x < 0) { sb.append('-'); x = -x; } x += Math.pow(10, -n) / 2; sb.append((long) x); sb.append("."); x -= (long) x; for (int i = 0; i < n; i++) { x *= 10; sb.append((int) x); x -= (int) x; } return sb.toString(); } @Override public void print(float f) { super.print(dtos(f, 20)); } @Override public void println(float f) { super.println(dtos(f, 20)); } @Override public void print(double d) { super.print(dtos(d, 20)); } @Override public void println(double d) { super.println(dtos(d, 20)); } public void printArray(int[] array, String separator) { int n = array.length; for (int i = 0; i < n - 1; i++) { super.print(array[i]); super.print(separator); } super.println(array[n - 1]); } public void printArray(int[] array) { this.printArray(array, " "); } public void printArray(int[] array, String separator, java.util.function.IntUnaryOperator map) { int n = array.length; for (int i = 0; i < n - 1; i++) { super.print(map.applyAsInt(array[i])); super.print(separator); } super.println(map.applyAsInt(array[n - 1])); } public void printArray(int[] array, java.util.function.IntUnaryOperator map) { this.printArray(array, " ", map); } public void printArray(long[] array, String separator) { int n = array.length; for (int i = 0; i < n - 1; i++) { super.print(array[i]); super.print(separator); } super.println(array[n - 1]); } public void printArray(long[] array) { this.printArray(array, " "); } public void printArray(long[] array, String separator, java.util.function.LongUnaryOperator map) { int n = array.length; for (int i = 0; i < n - 1; i++) { super.print(map.applyAsLong(array[i])); super.print(separator); } super.println(map.applyAsLong(array[n - 1])); } public void printArray(long[] array, java.util.function.LongUnaryOperator map) { this.printArray(array, " ", map); } } static class Permutation implements java.util.Iterator, Iterable { private int[] next; public Permutation(int n) { next = java.util.stream.IntStream.range(0, n).toArray(); } @Override public boolean hasNext() { return next != null; } @Override public int[] next() { int[] r = next.clone(); next = nextPermutation(next); return r; } @Override public java.util.Iterator iterator() { return this; } public static int[] nextPermutation(int[] a) { if (a == null || a.length < 2) return null; int p = 0; for (int i = a.length - 2; i >= 0; i--) { if (a[i] >= a[i + 1]) continue; p = i; break; } int q = 0; for (int i = a.length - 1; i > p; i--) { if (a[i] <= a[p]) continue; q = i; break; } if (p == 0 && q == 0) return null; int temp = a[p]; a[p] = a[q]; a[q] = temp; int l = p, r = a.length; while (++l < --r) { temp = a[l]; a[l] = a[r]; a[r] = temp; } return a; } } static class SegTree { final int MAX; final int N; final java.util.function.BinaryOperator op; final S E; final S[] data; @SuppressWarnings("unchecked") public SegTree(int n, java.util.function.BinaryOperator op, S e) { this.MAX = n; int k = 1; while (k < n) k <<= 1; this.N = k; this.E = e; this.op = op; this.data = (S[]) new Object[N << 1]; java.util.Arrays.fill(data, E); } public SegTree(S[] dat, java.util.function.BinaryOperator op, S e) { this(dat.length, op, e); build(dat); } private void build(S[] dat) { int l = dat.length; System.arraycopy(dat, 0, data, N, l); for (int i = N - 1; i > 0; i--) { data[i] = op.apply(data[i << 1 | 0], data[i << 1 | 1]); } } public void set(int p, S x) { exclusiveRangeCheck(p); data[p += N] = x; p >>= 1; while (p > 0) { data[p] = op.apply(data[p << 1 | 0], data[p << 1 | 1]); p >>= 1; } } public S get(int p) { exclusiveRangeCheck(p); return data[p + N]; } public S prod(int l, int r) { if (l > r) { throw new IllegalArgumentException(String.format("Invalid range: [%d, %d)", l, r)); } inclusiveRangeCheck(l); inclusiveRangeCheck(r); S sumLeft = E; S sumRight = E; l += N; r += N; while (l < r) { if ((l & 1) == 1) sumLeft = op.apply(sumLeft, data[l++]); if ((r & 1) == 1) sumRight = op.apply(data[--r], sumRight); l >>= 1; r >>= 1; } return op.apply(sumLeft, sumRight); } public S allProd() { return data[1]; } public int maxRight(int l, java.util.function.Predicate f) { inclusiveRangeCheck(l); if (!f.test(E)) { throw new IllegalArgumentException("Identity element must satisfy the condition."); } if (l == MAX) return MAX; l += N; S sum = E; do { l >>= Integer.numberOfTrailingZeros(l); if (!f.test(op.apply(sum, data[l]))) { while (l < N) { l = l << 1; if (f.test(op.apply(sum, data[l]))) { sum = op.apply(sum, data[l]); l++; } } return l - N; } sum = op.apply(sum, data[l]); l++; } while ((l & -l) != l); return MAX; } public int minLeft(int r, java.util.function.Predicate f) { inclusiveRangeCheck(r); if (!f.test(E)) { throw new IllegalArgumentException("Identity element must satisfy the condition."); } if (r == 0) return 0; r += N; S sum = E; do { r--; while (r > 1 && (r & 1) == 1) r >>= 1; if (!f.test(op.apply(data[r], sum))) { while (r < N) { r = r << 1 | 1; if (f.test(op.apply(data[r], sum))) { sum = op.apply(data[r], sum); r--; } } return r + 1 - N; } sum = op.apply(data[r], sum); } while ((r & -r) != r); return 0; } private void exclusiveRangeCheck(int p) { if (p < 0 || p >= MAX) { throw new IndexOutOfBoundsException( String.format("Index %d out of bounds for the range [%d, %d).", p, 0, MAX)); } } private void inclusiveRangeCheck(int p) { if (p < 0 || p > MAX) { throw new IndexOutOfBoundsException( String.format("Index %d out of bounds for the range [%d, %d].", p, 0, MAX)); } } // **************** DEBUG **************** // private int indent = 6; public void setIndent(int newIndent) { this.indent = newIndent; } @Override public String toString() { return toSimpleString(); } public String toDetailedString() { return toDetailedString(1, 0); } private String toDetailedString(int k, int sp) { if (k >= N) return indent(sp) + data[k]; String s = ""; s += toDetailedString(k << 1 | 1, sp + indent); s += "\n"; s += indent(sp) + data[k]; s += "\n"; s += toDetailedString(k << 1 | 0, sp + indent); return s; } private static String indent(int n) { StringBuilder sb = new StringBuilder(); while (n-- > 0) sb.append(' '); return sb.toString(); } public String toSimpleString() { StringBuilder sb = new StringBuilder(); sb.append('['); for (int i = 0; i < N; i++) { sb.append(data[i + N]); if (i < N - 1) sb.append(',').append(' '); } sb.append(']'); return sb.toString(); } } }