#include<bits/stdc++.h>
#define endl '\n'
using namespace std;
void solve()
{
    int n,h;
    cin>>n>>h;
    double sum=0;
    for(int i=0;i<n;i++)
    {
        double a,b;
        cin>>a>>b;
        sum+=(a+b)/2;
    }
    if(h-sum>0.000001)cout<<"NO\n";
    else cout<<"YES\n";
}
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);

    freopen("battle.in","r",stdin);
    freopen("battle.out","w",stdout);
    int t;
    cin>>t;
    while(t--)
    {
        solve();
    }
    return 0;
}