#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
        
        int q,n,x,y;
        cin>>q;
        while(q--){
            cin>>n;
            while(n--){
                cin>>x>>y;
                if(x!=0 && y!=0){
                    cout<<"YES\n";
                    break;
                }
            }
             if(q==0){
            cout<<"NO\n";
        }
        }
        

            
    return 0;
}