#include<bits/stdc++.h>
#define int long long
#define IOS ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
using namespace std;
const int N=1e9+10;


void solve(){ 
    int n,k;cin>>n>>k;
   int num[n];
    for(int i=1;i<=n;i++){
        num[i]+=k;
}
    for(int i=1;i<=n;i++){
        int a,b;
        cin>>a>>b;
        if(num[a]<b){cout<<"NO"<<endl;return;}
    }


    cout<<"YES"<<endl;







}



signed main(void){
    IOS
    int t=1;
    cin>>t;
    while(t--){
        solve();
    }
}