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

void solve(){
    ll N,M;
    cin>>N>>M;
    ll SB=0;
    ll L=-1e18,R=1e18;
    for(int i=0;i<M;i++){
        ll A,B;
        cin>>A>>B;
        R=min(R,A-SB);
        L=max(L,A-(SB+B-1));
        // cout<<A-SB<<" "<<A-(SB+B-1)<<endl;
        SB+=B;
    }
    cout<<(L<=R?"Yes\n":"No\n");
}

int main(){
	ios::sync_with_stdio(false);
    cin.tie(nullptr);

    ll T;
    cin>>T;
    while(T--)solve();
}