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


int main() {long int i,j,k,l,m,n,y,x,m1,n1,m2,n2,o;
            cin>>n;
            for(i=0;i<n;++i)
                {m1=n1=-100000;m2=n2=100000;o=0;
                cin>>m;vector <int >a,b;
           for(j=0;j<m;++j)
  {cin>>k>>l;a.push_back(k);b.push_back(l);if(k>m1)m1=k;if(l>n1)n1=l;if(k<m2)m2=k;if(l<n2)n2=l;}
 //       if(m<=3){cout<<"YES\n";continue;}
                 
                 for(j=0;j<m;++j)if(a[j]==m1||a[j]==m2||b[j]==n1||b[j]==n2)++o;if(o==m)cout<<"YES\n";else cout<<"NO\n";
                                  
            }
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    return 0;
}