#include using namespace std; #include #include using namespace atcoder; using ll = long long; using vll = vector; using vvll = vector; using vvvll = vector; using vb = vector; using vvb = vector; using vvvb = vector; #define all(A) A.begin(),A.end() #define rep(i, n) for (ll i = 0; i < (ll) (n); i++) template bool chmax(T& p, T q, bool C = 1) { if (C == 0 && p == q) { return 1; } if (p < q) { p = q; return 1; } else { return 0; } } template bool chmin(T& p, T q, bool C = 1) { if (C == 0 && p == q) { return 1; } if (p > q) { p = q; return 1; } else { return 0; } } ll modPow(long long a, long long n, long long p) { if (n == 0) return 1; // 0乗にも対応する場合 if (n == 1) return a % p; if (n % 2 == 1) return (a * modPow(a, n - 1, p)) % p; long long t = modPow(a, n / 2, p); return (t * t) % p; } ll cnt = 0; ll gcd(ll(a), ll(b)) { cnt++; if (a == 0)return b; if (b == 0)return a; ll c = a; while (a % b != 0) { c = a % b; a = b; b = c; } return b; } ll sqrtz(ll N) { ll L = 0; ll R = sqrt(N) + 10000; while (abs(R - L) > 1) { ll mid = (R + L) / 2; if (mid * mid <= N)L = mid; else R = mid; } return L; } ll nzkon(ll N, ll K) {// return 0; } using mint = modint998244353; using vm = vector; using vvm = vector; using vvvm = vector; vector fact, factinv, inv; const ll mod = 998244353; void prenCkModp(ll n) { fact.resize(n + 5); factinv.resize(n + 5); inv.resize(n + 5); fact[0] = fact[1] = 1; factinv[0] = factinv[1] = 1; inv[1] = 1; for (ll i = 2; i < n + 5; i++) { fact[i] = (fact[i - 1] * i); inv[i] = (mod - ((inv[mod % i] * (mod / i)))); factinv[i] = (factinv[i - 1] * inv[i]); } } mint nCk(ll n, ll k) { if (n < k || k < 0) return 0; return (fact[n] * ((factinv[k] * factinv[n - k]))); } bool DEB = 0; vvm mul(vvm A, vvm B) { ll n = A.size(); vvm res(n, vm(n, 0)); rep(i, n)rep(j, n)rep(k, n)res[i][j] += A[i][k] * B[k][j]; return res; } vvll G; vb seen; int main() { cin.tie(nullptr); ios::sync_with_stdio(false); ll N,K; cin>>N>>K; G.resize(N); seen.assign(N,1); vll E(N,0); rep(i,N){ ll U,V; cin>>U>>V; U--;V--; G[U].push_back(V); G[V].push_back(U); E[U]++; E[V]++; } queue P; rep(i,N)if(E[i]==1)P.push(i); while(!P.empty()){ ll p=P.front(); P.pop(); if(!seen[p])continue; seen[p]=0; for(auto v:G[p]){ E[v]--; if(E[v]==1)P.push(v); } } ll nam=0; rep(i,N)if(seen[i])nam++; vvm NC(nam,vm(2,0)); NC[0][0]=1; rep(i,nam-1){ NC[i+1][0]+=NC[i][1]; NC[i+1][1]+=NC[i][0]*(K-1)+NC[i][1]*(K-2); } mint an=NC[nam-1][1]*mint(K); an*=mint(K-1).pow(N-nam); cout<