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

const ll mod = 998'244'353;
//const ll mod = 1'000'000'007;
//const ll mod = 67'280'421'310'721;
struct mint{
    long long x;
    mint(long long x=0):x((x%mod+mod)%mod){}
    mint operator-() const{
        return mint(-x);
    }
    mint& operator+=(const mint& a){
        if((x+=a.x)>=mod)x-=mod;
        return *this;
    }
    mint& operator-=(const mint& a){
        if((x+=mod-a.x)>=mod)x-=mod;
        return *this;
    }
    mint& operator*=(const  mint& a){
        (x *= a.x) %= mod;
        return *this;
    }
    mint operator+(const mint& a) const{
        mint res(*this);
        return res+=a;
    }
    mint operator-(const mint& a) const{
        mint res(*this);
        return res-=a;
    }
    mint operator*(const mint& a) const{
        mint res(*this);
        return res*=a;
    }
    mint pow(long long n) const {
        assert(0 <= n);
        mint a = *this, r = 1;
        while (n) {
            if (n & 1) r *= a;
            a *= a;
            n >>= 1;
        }
        return r;
    }
    mint inv() const{
        return pow(mod-2);
    }
    mint& operator/=(const mint& a){
        return (*this)*=a.inv();
    }
    mint operator/(const mint& a) const {
        mint res(*this);
        return res/=a;
    }
    friend ostream& operator<<(ostream& os, const mint& m){
        os << m.x;
        return os;
    }
    bool operator==(const mint& a) const {
        return x == a.x;
    }
    bool operator<(const mint& a) const{
        return x < a.x;
    }
};

int main(){
    int n,k;
    cin>>n>>k;
    vector<pair<int,int>> use;
    mint ans = mint(k).pow(n);
    for(int i = 0;i<n;i++){
        int l,r;
        cin>>l>>r;
        use.push_back(make_pair(l,1));
        use.push_back(make_pair(r,0));
    }
    int rest = k;
    sort(use.begin(),use.end());
    mint tmp = 1;
    for(int i = 0;i<use.size();i++){
        pair<int,int> now = use[i];
        if(now.second==0) rest++;
        else{
            if(rest<=0) tmp = 0;
            else{
                tmp *= mint(rest--);
            }
        }
    }
    ans -= tmp;
    cout<<ans<<endl;
}