package contest200717; import java.io.ByteArrayInputStream; import java.io.IOException; import java.io.InputStream; import java.io.PrintWriter; import java.util.ArrayDeque; import java.util.Arrays; import java.util.HashMap; import java.util.HashSet; import java.util.InputMismatchException; import java.util.Map; import java.util.Queue; import java.util.Set; public class D { InputStream is; PrintWriter out; String INPUT = ""; void solve() { int n = ni(); int mod = 998244353; long all = 0; int[][] fif = enumFIF(n, mod); for(int i = 3;i <= n;i++){ // C(n,i)*(i-1)! all += C(n, i, mod, fif) * fif[0][i-1]; all %= mod; } all = all * invl(2, mod) % mod; int m = ni(); int[][] es = new int[m][]; for(int i = 0;i < m;i++){ es[i] = new int[]{ni()-1, ni()-1}; } long ans = all; Map cache = new HashMap<>(); outer: for(int i = 1;i < 1< deg = new HashMap<>(); for(int j = 0;j < m;j++){ if(i<<~j<0){ inc(es[j][0], deg); inc(es[j][1], deg); } } for(int v : deg.values()){ if(v >= 3)continue outer; } Set line = new HashSet<>(); Queue q = new ArrayDeque<>(); for(int k : deg.keySet()){ if(deg.get(k).equals(1)){ q.add(k); line.add(k); } } while(!q.isEmpty()){ int cur = q.poll(); for(int j = 0;j < m;j++){ if(i<<~j<0 && (es[j][0] == cur || es[j][1] == cur)){ int to = es[j][0]^es[j][1]^cur; if(!line.contains(to)){ line.add(to); q.add(to); } } } } if(line.size() < deg.size()){ // it has cycle Set cycle = new HashSet<>(); for(int k : deg.keySet()){ q.add(k); cycle.add(k); break; } while(!q.isEmpty()){ int cur = q.poll(); for(int j = 0;j < m;j++){ if(i<<~j<0 && (es[j][0] == cur || es[j][1] == cur)){ int to = es[j][0]^es[j][1]^cur; if(!cycle.contains(to)){ cycle.add(to); q.add(to); } } } } if(line.size() > 0 && cycle.size() > 0){ continue outer; } if(line.size() == 0 && cycle.size() != deg.size())continue outer; ans += (Integer.bitCount(i) % 2 == 1 ? mod-1 : 1) * 1; ans %= mod; continue outer; } int one = 0; int zero = n-deg.size(); for(int v : deg.values()){ if(v == 1)one++; } int con = one/2; long code = (long)zero<<32|con; if(!cache.containsKey(code)){ long w = 0; for(int k = 0;k <= zero;k++){ w += C(zero, k, mod, fif) * fif[0][con-1+k]; w %= mod; } cache.put(code, w); } long ww = cache.get(code); if(Integer.bitCount(i) == 1){ ww += mod - fif[0][con-1]; } ans += (Integer.bitCount(i) % 2 == 1 ? mod-1 : 1) * (pow(2, con-1, mod) % mod * ww % mod); ans %= mod; } out.println(ans); } public static long invl(long a, long mod) { long b = mod; long p = 1, q = 0; while (b > 0) { long c = a / b; long d; d = a; a = b; b = d % b; d = p; p = q; q = d - c * q; } return p < 0 ? p + mod : p; } public static long pow(long a, long n, long mod) { // a %= mod; long ret = 1; int x = 63 - Long.numberOfLeadingZeros(n); for (; x >= 0; x--) { ret = ret * ret % mod; if (n << 63 - x < 0) ret = ret * a % mod; } return ret; } public static void inc(T key, Map map){inc(key, 1, map);} public static void inc(T key, int inc, Map map){map.put(key, map.getOrDefault(key, 0) + inc);} public static void inc(T key, long inc, Map map){map.put(key, map.getOrDefault(key, 0L) + inc);} public static long C(int n, int r, int mod, int[][] fif) { if (n < 0 || r < 0 || r > n) return 0; return (long) fif[0][n] * fif[1][r] % mod * fif[1][n - r] % mod; } public static int[][] enumFIF(int n, int mod) { int[] f = new int[n + 1]; int[] invf = new int[n + 1]; f[0] = 1; for (int i = 1; i <= n; i++) { f[i] = (int) ((long) f[i - 1] * i % mod); } long a = f[n]; long b = mod; long p = 1, q = 0; while (b > 0) { long c = a / b; long d; d = a; a = b; b = d % b; d = p; p = q; q = d - c * q; } invf[n] = (int) (p < 0 ? p + mod : p); for (int i = n - 1; i >= 0; i--) { invf[i] = (int) ((long) invf[i + 1] * (i + 1) % mod); } return new int[][] { f, invf }; } void run() throws Exception { is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes()); out = new PrintWriter(System.out); long s = System.currentTimeMillis(); solve(); out.flush(); if(!INPUT.isEmpty())tr(System.currentTimeMillis()-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(); } public static void main(String[] args) throws Exception { new D().run(); } private 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 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))){ // when nextLine, (isSpaceChar(b) && 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 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 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 ni() { return (int)nl(); } 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(); } } private static void tr(Object... o) { System.out.println(Arrays.deepToString(o)); } }