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#include<bits/stdc++.h>
using namespace std;
int main(){
    int cas;
    cin>>cas;
    while(cas--){
        int n,m;
        cin>>n>>m;
        for(int i = 0; i < m; i++){
            int a, b;
            cin>>a>>b;
        }
        if(n - m == 1)
            cout<<"YES";
        else
            cout<<"NO";
        cout<<endl;
    }
}
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