#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,i,flag=1;
        cin>>n;
        long long int minx=10000,maxx=-10000,miny=10000,maxy=-10000;
        long long int x[n],y[n];
      for(int i=0;i<n;i++)
          {
          cin>>x[i]>>y[i];
if(x[i]<minx)
minx=x[i];
if(y[i]<miny)
miny=y[i];
if(x[i]>maxx)
maxx=x[i];
if(y[i]>maxy)
maxy=y[i];
      }
        for(i=0;i<n;i++)
            {
            if((minx!=x[i]) && (maxx!=x[i]) && (miny!=y[i]) && (maxy!=y[i]))
               flag=0;
        }
        if(!flag)
            cout<<"NO"<<endl;
        else
            cout<<"YES"<<endl;
       
      
    }
    return 0;
}