#include<bits/stdc++.h>
using namespace std;

#define debug(x) cerr << #x << " = " << (x) << endl
#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define mp make_pair
#define pb push_back
typedef long long ll;
typedef long double ld;
typedef pair<int, int> Pii;
typedef pair<ll, ll> Pll;

struct IOSetup
{
	IOSetup()
	{
		cin.tie(nullptr)->sync_with_stdio(false);
		cout << fixed << setprecision(16);
		cerr << fixed << setprecision(16);
	}
} iosetup;

template <typename T1, typename T2>
ostream &operator <<(ostream &os, const pair<T1, T2> &p)
{
	os << p.first << " " << p.second;
	return os;
}

template <typename T1, typename T2>
istream &operator >>(istream &is, pair<T1, T2> &p)
{
	is >> p.first >> p.second;
	return is;
}

template <typename T>
ostream &operator <<(ostream &os, const vector<T> &v)
{
	for(int i = 0; i < (int) v.size(); i++) os << v[i] << (i+1 == (int) v.size() ? "" : " ");
	return os;
}

template <typename T>
istream &operator >>(istream &is, vector<T> &v)
{
	for(int i = 0; i < (int) v.size(); i++) is >> v[i];
	return is;
}

template <typename T> bool chmax(T &a, const T &b) { if(a < b) { a = b; return true; } return false; }
template <typename T> bool chmin(T &a, const T &b) { if(a > b) { a = b; return true; } return false; }

////////////////////////////////////////////////////////

#include<atcoder/modint>
using mint = atcoder::modint998244353;
istream &operator >>(istream &is, mint &a)
{
	int x; is >> x;
	a = x;
	return is;
}
ostream &operator <<(ostream &os, const mint &a) { return os << a.val(); }

int main()
{
	int N, K; cin >> N >> K;
	vector<vector<int>> G(N);
	vector<int> deg(N);
	for(int i = 0; i < N; i++)
	{
		int u, v; cin >> u >> v;
		u--; v--;
		G[u].pb(v);
		G[v].pb(u);
		deg[u]++;
		deg[v]++;
	}

	vector<bool> visited(N, false), cycle(N, true);
	auto dfs = [&](auto &self, int now) -> void
	{
		if(deg[now] != 1) return;
		cycle[now] = false;
		if(visited[now]) return;
		visited[now] = true;
		for(int nxt : G[now])
		{
			if(visited[nxt]) continue;
			deg[nxt]--;
			if(deg[nxt] == 1) self(self, nxt);
		}
	};
	for(int i = 0; i < N; i++) dfs(dfs, i);
	
	int cnt = accumulate(all(cycle), 0), res = N - cnt;

	auto solve = [](auto &self, int N, int M) -> mint
	{
		if(N == 2) return mint(M) * (M-1);
		else return mint(M) * mint(M-1).pow(N-1) - self(self, N-1, M);
	};

	cout << mint(K-1).pow(res) * solve(solve, cnt, K) << endl;
	return 0;
}