#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <queue>
#include <deque>
#include <cmath>
#include <iomanip>
#include <set>
#include <map>
using namespace std;
using ll = long long;
using ld = long double;
constexpr ll MOD = 998244353;

ll modpow(ll a, ll x){
    ll res = 1;
    for(; x > 0; x >>= 1){
        if(x & 1){
            res *= a;
            res %= MOD;
        }
        a *= a;
        a %= MOD;
    }
    return res;
}

int main(){
    int n, k; cin >> n >> k;
    vector<int> l(n), r(n);
    for(int i = 0; i < n; i++) cin >> l[i] >> r[i];

    const int lim = 200010;
    vector<int> in(lim, 0), out(lim, 0);
    for(int i = 0; i < n; i++){
        in[l[i]]++;
        out[r[i]]++;
    }
    bool overlap = false;
    ll ans = 1;
    int cnt = 0;
    for(int i = 0; i < lim; i++){
        cnt -= out[i];
        for(int j = 0; j < in[i]; j++){
            if(cnt > 0) overlap = true;
            ans *= k-cnt;
            ans %= MOD;
            cnt++;
        }
    }

    cout << (modpow(k, n)-ans+MOD)%MOD << endl;
    return 0;
}