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


int main() {
    int test;
    cin>>test;
    while(test--)
        {
        int n,x,y,xmin=9999,xmax=-9999,ymax=-9999,ymin=9999,count=0;
        cin>>n;
        int a[n],b[n];
       for(int i=0;i<n;i++)
           {
           cin>>x>>y;
           if(x>xmax)
               xmax=x;
           if(y>ymax)
               ymax=y;
           if(x<xmin)
               xmin=x;
           if(y<ymin)
               ymin=y;
             a[i]=x;
             b[i]=y;
       }
       for(int i=0;i<n;i++)
           {
           if((a[i]==xmin||a[i]==xmax)||(b[i]==ymin||b[i]==ymax))
               count++;
       }
        if(count==n)
            cout<<"YES"<<endl;
        else
            cout<<"NO"<<endl;
        
    }
    return 0;
}