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


int main() {
    int i,j,k,l,t,m,n,a,b,c,x[100],y[100],mx_x,mx_y,mi_x,mi_y;
    cin>>t;
    while(t--)
        {
        cin>>n;
        mx_x=-10030,mx_y=-10034,mi_x=10034,mi_y=10034;
        for(i=0;i<n;i++)
            {
            cin>>x[i]>>y[i];
            if(mx_x<x[i])
                mx_x=x[i];
            if(mx_y<y[i])
                mx_y=y[i];
                        
              if(mi_x>x[i])
                mi_x=x[i];
              if(mi_y>y[i])
                mi_y=y[i];
           }
        for(i=0;i<n;i++)
            {
            c=0;
            if(x[i]!=mx_x&&x[i]!=mi_x&&y[i]!=mx_y&&y[i]!=mi_y)
                {
                cout<<"NO"<<endl;
               
                c=1;
                 break;
                
            }
            
        }
        if(c==0)
            {
            cout<<"YES"<<endl;
        }
        
    }
    return 0;
}