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

}