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


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    
    int q;
     cin>>q;
     while(q--)
         {
           int n;
         cin>>n;
        int  flag=0;
         while(n--)
             {
               int x,y;
              cin>>x>>y;
               if(x==0 || y==0)
                   {
                     flag=1;
               }
             else
                 flag=0;
         }
         if(flag==0)
             cout<<"NO"<<endl;
         else
             cout<<"YES"<<endl;
         }
    
     
         return 0;
}