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


int main() {
    int q,n;
    cin>>q;
    for(int u=0;u<q;u++){
        cin>>n;
        int x[n],y[n];
        for(int i=0;i<n;i++)
            cin>>x[i]>>y[i];
        int xmin=x[0],ymin=y[0],xmax=x[0],ymax=y[0];
        for(int i=0;i<n;i++){
            if(x[i]<xmin)
                xmin=x[i];
            if(x[i]>xmax)
                xmax=x[i];
            if(y[i]<ymin)
                ymin=y[i];
            if(y[i]>ymax)
                ymax=y[i];
        }
        
        int i=0;
        for(i=0;i<n;i++)
            {
            if(x[i]==xmin || x[i]==xmax || y[i]==ymin || y[i]==ymax)
                continue;
            else
                break;
        }
        if(i==n)
            cout<<"YES\n";
        else
            cout<<"NO\n";
    }
    
    
    return 0;
}