#include <stdio.h>
#include <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
using namespace atcoder;
using mint = modint998244353;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf32 1000000001
#define Inf64 4000000000000000001



int main(){
	
	vector<int> l(200005,0),r(200005,0);
	
	int N,K;
	cin>>N>>K;
	rep(i,N){
		int a,b;
		cin>>a>>b;
		l[a]++;
		r[b]++;
	}
	
	int cur = K;
	mint ans = 1;
	rep(i,l.size()){
		rep(j,r[i])cur++;
		rep(j,l[i]){
			ans *= cur;
			cur--;
		}
	}
	ans = mint(K).pow(N) - ans;
	cout<<ans.val()<<endl;
	
	return 0;
}