#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 T,I;
    cin>>T;
    for(I=0;I<T;I++)
        {
            int n,i,xmax,xmin,ymax,ymin,buzz=1;
        cin>>n;
        vector <int> x(n);
        vector <int> y(n);
        for(i=0;i<n;i++)
            cin>>x[i]>>y[i];
        xmin=10000;
        for(i=0;i<n;i++)
        {
            if(xmin>x[i])
                xmin=x[i];
        }
         xmax=-10000;
        for(i=0;i<n;i++)
        {
            if(xmax<x[i])
                xmax=x[i];
        }
        ymin=10000;
        for(i=0;i<n;i++)
        {
            if(ymin>y[i])
                ymin=y[i];
        }
          ymax=-10000;
        for(i=0;i<n;i++)
        {
            if(ymax<y[i])
                ymax=y[i];
        }
        
        for(i=0;i<n;i++)
        {
           if((x[i]!=xmax)&&(x[i]!=xmin)&&(y[i]!=ymax)&&(y[i]!=ymin))
               {
               buzz=0;
               break;
           }
        } 
        if(buzz)
            cout<<"YES"<<endl;
        else 
            cout<<"NO"<<endl;
        }
    return 0;
}