#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using ll = long long;
#define rep(i,n) for(int i=0;i<(int)(n);i++)
using mint = atcoder::modint998244353;

int main(){
	int n,k;
	cin>>n>>k;
	vector<vector<int>> g(n);
	vector<int> tn(n,0);
	rep(i,n){
		int u,v;
		cin>>u>>v;
		u--; v--;
		g.at(u).push_back(v);
		g.at(v).push_back(u);
		tn.at(u)++;
		tn.at(v)++;
	}
	queue<int> cn1;
	rep(i,n) if(tn.at(i)==1) cn1.push(i);
	while(!cn1.empty()){
		int x=cn1.front();
		cn1.pop();
		for(int y:g.at(x)){
			tn.at(y)--;
			if(tn.at(y)==1) cn1.push(y);
		}
	}
	mint ans=1;
	int lp=0;
	rep(i,n) if(tn.at(i)==2) lp++;
	ans*=mint(k-1).pow(n-lp);
	vector<vector<mint>> dp(lp,vector<mint>(2,0));
	dp.at(0).at(0)=k;
	rep(i,lp-1){
		dp.at(i+1).at(0)+=dp.at(i).at(1);
		dp.at(i+1).at(1)+=dp.at(i).at(0)*(k-1);
		dp.at(i+1).at(1)+=dp.at(i).at(1)*(k-2);
	}
	ans*=dp.at(lp-1).at(1);
	cout<<ans.val()<<endl;
}