#include using namespace std; #define rep(i, n) for(int i = 0; i < n; i++) #define rep2(i, x, n) for(int i = x; i <= n; i++) #define rep3(i, x, n) for(int i = x; i >= n; i--) #define elif else if #define sp(x) fixed << setprecision(x) #define pb push_back #define eb emplace_back #define all(x) x.begin(), x.end() #define sz(x) (int)x.size() using ll = long long; using ld = long double; using pii = pair; using pil = pair; using pli = pair; using pll = pair; //const ll MOD = 1e9+7; const ll MOD = 998244353; const int inf = (1<<30)-1; const ll INF = (1LL<<60)-1; const ld EPS = 1e-10; template bool chmax(T &x, const T &y) {return (x < y)? (x = y, true) : false;}; template bool chmin(T &x, const T &y) {return (x > y)? (x = y, true) : false;}; template struct Mod_Int{ ll x; Mod_Int() {} Mod_Int(ll y) : x (y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {} Mod_Int &operator += (const Mod_Int &p){ x = (x + p.x) % mod; return *this; } Mod_Int &operator -= (const Mod_Int &p){ x = (x + mod - p.x) % mod; return *this; } Mod_Int &operator *= (const Mod_Int &p){ x = (x * p.x) % mod; return *this; } Mod_Int &operator /= (const Mod_Int &p){ *this *= p.inverse(); return *this; } Mod_Int &operator ++ () {return *this += Mod_Int(1);} Mod_Int operator ++ (int){ Mod_Int tmp = *this; ++*this; return tmp; } Mod_Int &operator -- () {return *this -= Mod_Int(1);} Mod_Int operator -- (int){ Mod_Int tmp = *this; --*this; return tmp; } Mod_Int operator - () const {return Mod_Int(-x);} Mod_Int operator + (const Mod_Int &p) const {return Mod_Int(*this) += p;} Mod_Int operator - (const Mod_Int &p) const {return Mod_Int(*this) -= p;} Mod_Int operator * (const Mod_Int &p) const {return Mod_Int(*this) *= p;} Mod_Int operator / (const Mod_Int &p) const {return Mod_Int(*this) /= p;} bool operator == (const Mod_Int &p) const {return x == p.x;} bool operator != (const Mod_Int &p) const {return x != p.x;} Mod_Int pow(ll n) const{ Mod_Int now = *this, ret = 1; while(n > 0){ if(n & 1) ret *= now; now *= now, n >>= 1; } return ret; } Mod_Int inverse() const{ return pow(mod-2); } friend ostream &operator << (ostream &os, const Mod_Int &p){ return os << p.x; } friend istream &operator >> (istream &is, Mod_Int &p){ ll a; is >> a; p = Mod_Int(a); return is; } }; using mint = Mod_Int; const int MAX_N = 1e6; mint fac[MAX_N+1], ifac[MAX_N+1]; void init(){ fac[0] = 1; rep2(i, 1, MAX_N){ fac[i] = fac[i-1]*i; } ifac[MAX_N] = fac[MAX_N].inverse(); rep3(i, MAX_N, 1){ ifac[i-1] = ifac[i]*i; } } mint comb(int n, int k){ return fac[n]*ifac[n-k]*ifac[k]; } mint perm(int n, int k){ return fac[n]*ifac[n-k]; } struct Union_Find_Tree{ vector par, rank, num; Union_Find_Tree(int N){ par.assign(N, -1); rank.assign(N, 0); num.assign(N, 1); } int root(int x){ if(par[x] < 0 || par[x] == x) return x; return par[x] = root(par[x]); } void unite(int x, int y){ x = root(x), y = root(y); if(x == y) return; elif(rank[x] < rank[y]) par[x] = y, num[y] += num[x]; else{ par[y] = x, num[x] += num[y]; if(rank[x] == rank[y]) rank[x]++; } } int size(int x) {return num[root(x)];} bool same(int x, int y){ return root(x) == root(y); } void clear(){ fill(par.begin(), par.end(), -1); fill(rank.begin(), rank.end(), 0); fill(num.begin(), num.end(), 1); } }; int main(){ int N, M; cin >> N >> M; int u[M], v[M]; rep(i, M) { cin >> u[i] >> v[i]; u[i]--, v[i]--; } mint ans = 0; init(); rep2(i, 3, N) ans += comb(N, i)*fac[i-1]/2; mint num[2*M+1][M+1]; rep(i, 2*M+1){ int n = N-i; if(n < 0) continue; rep2(j, 1, M){ num[i][j] = 0; rep2(k, 0, n){ num[i][j] += perm(n, k)*comb(k+j-1, k); } if(i == 2 && j == 1) num[i][j]--; } } map mp; rep2(i, 1, (1<= 3) flag = true; elif(e.second == 2) cnt2++; else cnt1++; e.second = n++; } Union_Find_Tree uft(n); int circle = 0; rep(j, M){ if(!(i&(1<= 2) flag = true; cnt1 /= 2; mp.clear(); if(flag) continue; mint tmp; if(cnt1 == 0) tmp = 1; else tmp = fac[cnt1-1]*mint(2).pow(cnt1-1)*num[cnt2+cnt1*2][cnt1]; if(__builtin_popcount(i)%2 == 0) ans += tmp; else ans -= tmp; } cout << ans << endl; }