#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;
    for(int i = 0; i < q; i++)
    {
        int n;
        cin>>n;
        int x[n],y[n];
        int x1 = pow(10,4),x2 = -pow(10,4),y1 = pow(10,4),y2 = -pow(10,4);
        int countx=0,county=0;
        for(int j = 0; j < n; j++)
        {
            cin>>x[j]>>y[j];
        }
        for(int j = 0; j < n; j++)
        {
            if(x[j] < x1)
            {
                x1 = x[j];
            }
            if(y[j] < y1)
            {
                y1 = y[j];
            }
        }
        for(int j = 0; j < n; j++)
        {
            if(x[j] > x2)
            {
                x2 = x[j];
            }
            if(y[j] > y2)
            {
                y2 = y[j];
            }
        }
        for(int j = 0; j < n; j++)
        {
            if((x[j]>x1 && x[j]<x2) && (y[j]>y1 && y[j] <y2))
            {
                cout<<"NO\n";
                break;
            }
            if(j == n-1)
            {
                cout<<"YES\n";
                break;
            }
        }
    }
    return 0;
}