package contest230908; import java.io.*; import java.util.*; import java.util.function.IntUnaryOperator; import java.util.function.LongUnaryOperator; public class E { InputStream is; FastWriter out; String INPUT = ""; public void solve() { int n = ni(); int m = ni(); int[][] es = nmi(m, 2); int[] indeg = new int[n]; int[] outdeg = new int[n]; for(int i = 0;i < m;i++){ int u = es[i][0] - 1; int v = es[i][1] - 1; indeg[v]++; outdeg[u]++; } List eds = new ArrayList<>(); int src = n, sink = n+1; for(int i = 0;i < n;i++){ if(indeg[i] > outdeg[i]){ eds.add(new Edge(i, sink, indeg[i]-outdeg[i])); }else{ eds.add(new Edge(src, i, outdeg[i]-indeg[i])); } } for(int i = 0;i < m;i++){ int u = es[i][0] - 1; int v = es[i][1] - 1; eds.add(new Edge(u, v, 1)); } Edge[][] g = compileWD(n+2, eds); long flow = maximumFlowDinic(g, src, sink); List ans = new ArrayList<>(); for(Edge e : eds){ // if(!e.cloned) { // out.print(e.from + " "); // out.print(e.to + " "); // out.print(e.flow + "\n"); // } // tr(e.from, e.to, e.flow); if(!e.cloned && e.from < src && e.to < src && e.flow > 0){ ans.add(new int[]{e.from+1, e.to+1}); } } out.println(n + " " + ans.size()); for(int[] e : ans){ out.println(e[0] + " " + e[1]); } } public static class Edge { public int from, to; public long capacity; public long flow; public Edge complement; public boolean cloned; public Edge(int from, int to, long capacity) { this.from = from; this.to = to; this.capacity = capacity; } } public static void reset(Edge[][] g) { for(Edge[] row : g){ for(Edge e : row){ e.flow = e.cloned ? e.capacity : 0; } } } public static Edge[][] compileWD(int n, List edges) { Edge[][] g = new Edge[n][]; // cloning for(int i = edges.size()-1;i >= 0;i--){ Edge origin = edges.get(i); Edge clone = new Edge(origin.to, origin.from, origin.capacity); clone.flow = origin.capacity; clone.complement = origin; clone.cloned = true; origin.complement = clone; edges.add(clone); } int[] p = new int[n]; for(Edge e : edges)p[e.from]++; for(int i = 0;i < n;i++)g[i] = new Edge[p[i]]; for(Edge e : edges)g[e.from][--p[e.from]] = e; return g; } public static Edge[][] compileWU(int n, List edges) { Edge[][] g = new Edge[n][]; // cloning for(int i = edges.size()-1;i >= 0;i--){ Edge origin = edges.get(i); Edge clone = new Edge(origin.to, origin.from, origin.capacity*2); origin.flow = origin.capacity; clone.flow = origin.capacity; clone.complement = origin; clone.cloned = true; origin.complement = clone; origin.capacity *= 2; edges.add(clone); } int[] p = new int[n]; for(Edge e : edges)p[e.from]++; for(int i = 0;i < n;i++)g[i] = new Edge[p[i]]; for(Edge e : edges)g[e.from][--p[e.from]] = e; return g; } public static long maximumFlowDinic(Edge[][] g, int source, int sink) { int n = g.length; int[] d = new int[n]; int[] q = new int[n]; long ret = 0; while(true){ Arrays.fill(d, -1); q[0] = source; int r = 1; d[source] = 0; for(int v = 0;v < r;v++){ int cur = q[v]; for(Edge ne : g[cur]){ if(d[ne.to] == -1 && ne.capacity - ne.flow > 0) { q[r++] = ne.to; d[ne.to] = d[cur] + 1; } } } if(d[sink] == -1)break; int[] sp = new int[n]; for(int i = 0;i < n;i++)sp[i] = g[i].length - 1; ret += dfsDinic(d, g, sp, source, sink, Long.MAX_VALUE); } return ret; } private static long dfsDinic(int[] d, Edge[][] g, int[] sp, int cur, int sink, long min) { if(cur == sink)return min; long left = min; for(int i = sp[cur];i >= 0;i--){ Edge ne = g[cur][i]; if(d[ne.to] == d[cur]+1 && ne.capacity - ne.flow > 0){ long fl = dfsDinic(d, g, sp, ne.to, sink, Math.min(left, ne.capacity - ne.flow)); if(fl > 0){ left -= fl; ne.flow += fl; ne.complement.flow -= fl; if(left == 0){ sp[cur] = i; return min; } } } } sp[cur] = -1; return min-left; } public static long maximumFlowDinicNoRec(Edge[][] g, int source, int sink) { int n = g.length; int[] d = new int[n]; // distance int[] q = new int[n]; // queue for BFS long ret = 0; int[] stack = new int[n]; long[] lefts = new long[n]; // left to flow long[] parflow = new long[n]; int[] probe = new int[n]; // search pointer while(true){ // BFS Arrays.fill(d, -1); q[0] = source; int r = 1; d[source] = 0; for(int v = 0;v < r;v++){ int cur = q[v]; for(Edge ne : g[cur]){ if(d[ne.to] == -1 && ne.capacity - ne.flow > 0) { q[r++] = ne.to; d[ne.to] = d[cur] + 1; } } } if(d[sink] == -1)break; // DFS for(int i = 0;i < n;i++)probe[i] = g[i].length-1; int sp = 0; stack[sp] = source; lefts[sp] = Long.MAX_VALUE / 10; parflow[sp] = 0; sp++; long delta = 0; boolean down = true; while(sp > 0){ int cur = stack[sp-1]; long left = lefts[sp-1]; if(cur == sink){ delta += left; parflow[sp-1] = left; sp--; down = false; continue; } if(!down){ if(parflow[sp] > 0){ lefts[sp-1] -= parflow[sp]; left = lefts[sp-1]; Edge ne = g[cur][probe[cur]]; ne.flow += parflow[sp]; ne.complement.flow -= parflow[sp]; parflow[sp-1] += parflow[sp]; } if(left > 0)probe[cur]--; } if(left > 0 && probe[cur] >= 0){ down = true; Edge ne = g[cur][probe[cur]]; if(d[ne.to] == d[cur]+1 && ne.capacity - ne.flow > 0){ lefts[sp] = Math.min(left, ne.capacity - ne.flow); stack[sp] = ne.to; parflow[sp] = 0; sp++; }else{ probe[cur]--; } }else{ down = false; sp--; } } ret += delta; } return ret; } /** * sourceに一番近い最小カットを返す。 * source側がtrue, sink側がfalse * * @param g * @param source * @param sink * @return */ public static boolean[] restoreCutPessimistically(Edge[][] g, int src) { int n = g.length; boolean[] ved = new boolean[n]; ved[src] = true; int[] q = new int[n]; int p = 0; q[p++] = src; for(int r = 0;r < p;r++){ int cur = q[r]; for(Edge e : g[cur]){ assert e.from == cur; if(e.flow < e.capacity && !ved[e.to]){ ved[e.to] = true; q[p++] = e.to; } } } return ved; } public static void main(String[] args) { new E().run(); } public void run() { long S = System.currentTimeMillis(); is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes()); out = new FastWriter(System.out); solve(); out.flush(); long G = System.currentTimeMillis(); tr(G-S+"ms"); // Thread t = new Thread(null, null, "~", Runtime.getRuntime().maxMemory()){ // @Override // public void run() { // long s = System.currentTimeMillis(); // solve(); // out.flush(); // if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms"); // } // }; // t.start(); // t.join(); } private boolean eof() { if(lenbuf == -1)return true; int lptr = ptrbuf; while(lptr < lenbuf)if(!isSpaceChar(inbuf[lptr++]))return false; try { is.mark(1000); while(true){ int b = is.read(); if(b == -1){ is.reset(); return true; }else if(!isSpaceChar(b)){ is.reset(); return false; } } } catch (IOException e) { return true; } } private final byte[] inbuf = new byte[1024]; public int lenbuf = 0, ptrbuf = 0; private int readByte() { if(lenbuf == -1)throw new InputMismatchException(); if(ptrbuf >= lenbuf){ ptrbuf = 0; try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); } if(lenbuf <= 0)return -1; } return inbuf[ptrbuf++]; } private boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); } // private boolean isSpaceChar(int c) { return !(c >= 32 && c <= 126); } private int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; } private double nd() { return Double.parseDouble(ns()); } private char nc() { return (char)skip(); } private String ns() { int b = skip(); StringBuilder sb = new StringBuilder(); while(!(isSpaceChar(b))){ sb.appendCodePoint(b); b = readByte(); } return sb.toString(); } private char[] ns(int n) { char[] buf = new char[n]; int b = skip(), p = 0; while(p < n && !(isSpaceChar(b))){ buf[p++] = (char)b; b = readByte(); } return n == p ? buf : Arrays.copyOf(buf, p); } private char[][] nm(int n, int m) { char[][] map = new char[n][]; for(int i = 0;i < n;i++)map[i] = ns(m); return map; } private int[][] nmi(int n, int m) { int[][] map = new int[n][]; for(int i = 0;i < n;i++)map[i] = na(m); return map; } private int[] na(int n) { int[] a = new int[n]; for(int i = 0;i < n;i++)a[i] = ni(); return a; } private long[] nal(int n) { long[] a = new long[n]; for(int i = 0;i < n;i++)a[i] = nl(); return a; } private int ni() { int num = 0, b; boolean minus = false; while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-')); if(b == '-'){ minus = true; b = readByte(); } while(true){ if(b >= '0' && b <= '9'){ num = num * 10 + (b - '0'); }else{ return minus ? -num : num; } b = readByte(); } } private long nl() { long num = 0; int b; boolean minus = false; while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-')); if(b == '-'){ minus = true; b = readByte(); } while(true){ if(b >= '0' && b <= '9'){ num = num * 10 + (b - '0'); }else{ return minus ? -num : num; } b = readByte(); } } public static class FastWriter { private static final int BUF_SIZE = 1<<13; private final byte[] buf = new byte[BUF_SIZE]; private final OutputStream out; private int ptr = 0; private FastWriter(){out = null;} public FastWriter(OutputStream os) { this.out = os; } public FastWriter(String path) { try { this.out = new FileOutputStream(path); } catch (FileNotFoundException e) { throw new RuntimeException("FastWriter"); } } public FastWriter write(byte b) { buf[ptr++] = b; if(ptr == BUF_SIZE)innerflush(); return this; } public FastWriter write(char c) { return write((byte)c); } public FastWriter write(char[] s) { for(char c : s){ buf[ptr++] = (byte)c; if(ptr == BUF_SIZE)innerflush(); } return this; } public FastWriter write(String s) { s.chars().forEach(c -> { buf[ptr++] = (byte)c; if(ptr == BUF_SIZE)innerflush(); }); return this; } private static int countDigits(int l) { if (l >= 1000000000) return 10; if (l >= 100000000) return 9; if (l >= 10000000) return 8; if (l >= 1000000) return 7; if (l >= 100000) return 6; if (l >= 10000) return 5; if (l >= 1000) return 4; if (l >= 100) return 3; if (l >= 10) return 2; return 1; } public FastWriter write(int x) { if(x == Integer.MIN_VALUE){ return write((long)x); } if(ptr + 12 >= BUF_SIZE)innerflush(); if(x < 0){ write((byte)'-'); x = -x; } int d = countDigits(x); for(int i = ptr + d - 1;i >= ptr;i--){ buf[i] = (byte)('0'+x%10); x /= 10; } ptr += d; return this; } private static int countDigits(long l) { if (l >= 1000000000000000000L) return 19; if (l >= 100000000000000000L) return 18; if (l >= 10000000000000000L) return 17; if (l >= 1000000000000000L) return 16; if (l >= 100000000000000L) return 15; if (l >= 10000000000000L) return 14; if (l >= 1000000000000L) return 13; if (l >= 100000000000L) return 12; if (l >= 10000000000L) return 11; if (l >= 1000000000L) return 10; if (l >= 100000000L) return 9; if (l >= 10000000L) return 8; if (l >= 1000000L) return 7; if (l >= 100000L) return 6; if (l >= 10000L) return 5; if (l >= 1000L) return 4; if (l >= 100L) return 3; if (l >= 10L) return 2; return 1; } public FastWriter write(long x) { if(x == Long.MIN_VALUE){ return write("" + x); } if(ptr + 21 >= BUF_SIZE)innerflush(); if(x < 0){ write((byte)'-'); x = -x; } int d = countDigits(x); for(int i = ptr + d - 1;i >= ptr;i--){ buf[i] = (byte)('0'+x%10); x /= 10; } ptr += d; return this; } public FastWriter write(double x, int precision) { if(x < 0){ write('-'); x = -x; } x += Math.pow(10, -precision)/2; // if(x < 0){ x = 0; } write((long)x).write("."); x -= (long)x; for(int i = 0;i < precision;i++){ x *= 10; write((char)('0'+(int)x)); x -= (int)x; } return this; } public FastWriter writeln(char c){ return write(c).writeln(); } public FastWriter writeln(int x){ return write(x).writeln(); } public FastWriter writeln(long x){ return write(x).writeln(); } public FastWriter writeln(double x, int precision){ return write(x, precision).writeln(); } public FastWriter write(int... xs) { boolean first = true; for(int x : xs) { if (!first) write(' '); first = false; write(x); } return this; } public FastWriter write(long... xs) { boolean first = true; for(long x : xs) { if (!first) write(' '); first = false; write(x); } return this; } public FastWriter write(IntUnaryOperator f, int... xs) { boolean first = true; for(int x : xs) { if (!first) write(' '); first = false; write(f.applyAsInt(x)); } return this; } public FastWriter write(LongUnaryOperator f, long... xs) { boolean first = true; for(long x : xs) { if (!first) write(' '); first = false; write(f.applyAsLong(x)); } return this; } public FastWriter writeln() { return write((byte)'\n'); } public FastWriter writeln(int... xs) { return write(xs).writeln(); } public FastWriter writeln(long... xs) { return write(xs).writeln(); } public FastWriter writeln(IntUnaryOperator f, int... xs) { return write(f, xs).writeln(); } public FastWriter writeln(LongUnaryOperator f, long... xs) { return write(f, xs).writeln(); } public FastWriter writeln(char[] line) { return write(line).writeln(); } public FastWriter writeln(char[]... map) { for(char[] line : map)write(line).writeln();return this; } public FastWriter writeln(String s) { return write(s).writeln(); } private void innerflush() { try { out.write(buf, 0, ptr); ptr = 0; } catch (IOException e) { throw new RuntimeException("innerflush"); } } public void flush() { innerflush(); try { out.flush(); } catch (IOException e) { throw new RuntimeException("flush"); } } public FastWriter print(byte b) { return write(b); } public FastWriter print(char c) { return write(c); } public FastWriter print(char[] s) { return write(s); } public FastWriter print(String s) { return write(s); } public FastWriter print(int x) { return write(x); } public FastWriter print(long x) { return write(x); } public FastWriter print(double x, int precision) { return write(x, precision); } public FastWriter println(char c){ return writeln(c); } public FastWriter println(int x){ return writeln(x); } public FastWriter println(long x){ return writeln(x); } public FastWriter println(double x, int precision){ return writeln(x, precision); } public FastWriter print(int... xs) { return write(xs); } public FastWriter print(long... xs) { return write(xs); } public FastWriter print(IntUnaryOperator f, int... xs) { return write(f, xs); } public FastWriter print(LongUnaryOperator f, long... xs) { return write(f, xs); } public FastWriter println(int... xs) { return writeln(xs); } public FastWriter println(long... xs) { return writeln(xs); } public FastWriter println(IntUnaryOperator f, int... xs) { return writeln(f, xs); } public FastWriter println(LongUnaryOperator f, long... xs) { return writeln(f, xs); } public FastWriter println(char[] line) { return writeln(line); } public FastWriter println(char[]... map) { return writeln(map); } public FastWriter println(String s) { return writeln(s); } public FastWriter println() { return writeln(); } } public static void trnz(int... o) { for(int i = 0;i < o.length;i++)if(o[i] != 0)System.out.print(i+":"+o[i]+" "); System.out.println(); } // print ids which are 1 public static void trt(long... o) { Queue stands = new ArrayDeque<>(); for(int i = 0;i < o.length;i++){ for(long x = o[i];x != 0;x &= x-1)stands.add(i<<6|Long.numberOfTrailingZeros(x)); } System.out.println(stands); } public static void tf(boolean... r) { for(boolean x : r)System.out.print(x?'#':'.'); System.out.println(); } public static void tf(boolean[]... b) { for(boolean[] r : b) { for(boolean x : r)System.out.print(x?'#':'.'); System.out.println(); } System.out.println(); } public void tf(long[]... b) { if(INPUT.length() != 0) { for (long[] r : b) { for (long x : r) { for (int i = 0; i < 64; i++) { System.out.print(x << ~i < 0 ? '#' : '.'); } } System.out.println(); } System.out.println(); } } public void tf(long... b) { if(INPUT.length() != 0) { for (long x : b) { for (int i = 0; i < 64; i++) { System.out.print(x << ~i < 0 ? '#' : '.'); } } System.out.println(); } } private void tr(Object... o) { if(INPUT.length() != 0)System.out.println(Arrays.deepToString(o)); } }