#include using namespace std; const int64_t MOD = 998244353; void add(int64_t& a, int64_t b){ a = (a+b) % MOD; } void mul(int64_t& a, int64_t b){ a = a*b % MOD; } int64_t power_mod(int64_t num, int64_t power){ int64_t prod = 1; num %= MOD; while(power > 0){ if(power&1) prod = prod * num % MOD; num = num * num % MOD; power >>= 1; } return prod; } int64_t extgcd(int64_t a, int64_t b, int64_t& x, int64_t& y){ int64_t d = a; if(b != 0){ d = extgcd(b, a%b, y, x); y -= (a/b) * x; }else{ x = 1; y = 0; } return d; } int64_t inv_mod(int64_t a){ int64_t x, y; extgcd(a, MOD, x, y); return (MOD + x%MOD) % MOD; } vector fact, fact_inv; void create_mod_tables(int num){ fact.assign(num+1, 1); fact_inv.assign(num+1, 1); for(int i=1; i<=num; i++) fact[i] = fact[i-1] * i % MOD; fact_inv[num] = inv_mod(fact[num]); for(int i=num; i>0; i--) fact_inv[i-1] = fact_inv[i] * i % MOD; } int64_t comb_mod(int n, int k){ return fact[n] * fact_inv[n-k] % MOD * fact_inv[k] % MOD; } int64_t perm_mod(int n, int k){ return fact[n] * fact_inv[n-k] % MOD; } int nth_bit(int64_t num, int n){ return (num >> n) & 1; } struct UnionFind { vector par; vector sz; UnionFind(int n=0){ if(n>0) initialize(n); } void initialize(int n){ par.resize(n); sz.assign(n, 1); for(int i=0; i sz[y]) swap(x, y); par[x] = y; sz[y] += sz[x]; return true; } bool same(int x, int y){ return find(x) == find(y); } int size(int x){ return sz[find(x)]; } }; template vector compress(vector A){ sort(A.begin(), A.end()); A.erase(unique(A.begin(), A.end()), A.end()); return A; } int main(){ int N, M; cin >> N >> M; vector A(M), B(M), V; for(int i=0; i> A[i] >> B[i]; A[i]--; B[i]--; V.push_back(A[i]); V.push_back(B[i]); } V = compress(V); int sz = V.size(); for(int& a : A) a = lower_bound(V.begin(), V.end(), a) - V.begin(); for(int& a : B) a = lower_bound(V.begin(), V.end(), a) - V.begin(); create_mod_tables(200000); // use, path static int64_t P[31][16]; for(int use=0; use<=2*M; use++) for(int path=0; path<=M; path++){ int rest = N-use; if(rest < 0) continue; int64_t p2 = power_mod(2, path); mul(p2, inv_mod(2)); for(int r=0; r<=rest; r++) if(use+r >= 3 && path+r){ int64_t res = comb_mod(rest, r) * fact[path+r-1] % MOD * p2 % MOD; //cerr << use< deg(sz); UnionFind uf(sz); int64_t C = 1; for(int i=0; i 2) continue; int use = 0, cmp = 0, one = 0; for(int i=0; i