#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N=2e6+10;
int n,m,k,ans,f[N+10],b[N+10],a[N+10],bb[N+10],mod=998244353;
int qsm(int x,int y){
    int sum=y,cnt=x,ans=1;
    while(sum>0){
        if(sum%2==1) ans=(cnt*ans)%mod;
        cnt=(cnt*cnt)%mod;
        sum=sum/2;
    }
    return ans;
}
int C(int a1,int b1){
	if(a1<0||b1<0||a1>b1) return 0;
    return f[b1]*b[a1]%mod*b[b1-a1]%mod;
} 
signed main(){
  freopen("BBQ.in","r",stdin);
  freopen("BBQ.out","w",stdout);
    ios::sync_with_stdio(false);
    cin.tie(0),cout.tie(0);
    cin>>n>>mod;
    f[0]=1;
    for(int i=1;i<N;i++) f[i]=(f[i-1]*i)%mod;
    for(int i=0;i<N;i++) b[i]=qsm(f[i],mod-2);
    for(int i=1;i<=n;i++){
        cin>>a[i]>>bb[i];
    }
    for(int i=1;i<=n;i++){
        for(int j=i+1;j<=n;j++){
//            cout<<C(a[i]+a[j],a[i]+a[j]+b[i]+b[j])<<endl;
            ans=(ans+C(a[i]+a[j],a[i]+a[j]+bb[i]+bb[j])%mod)%mod;
        }
    }
    cout<<ans<<endl;
}