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


int main() {
    //initalize
    int queries, points, temp;
    bool flag = false;
    cin >> queries;
    
    //for each query
    for (int i = 0; i < queries; i++){
        cin >> points;
        int x[points];
        int y[points];
        //add points to arrays
        for (int j = 0; j < points; j++){
           int temp;
            cin >> temp;
            x[j] = temp;
            cin >> temp;
            y[j] = temp;
        }
        
        //find max and min for x and y
        int xmax = x[0];
        int xmin = x[0];
        int ymax = y[0];
        int ymin = y[0];
        for (int j = 1; j < points; j++){
            if (x[j] > xmax)
                xmax = x[j];
            if (x[j] < xmin)
                xmin = x[j];
        }
        
        for (int j = 1; j < points; j++){
            if (y[j] > ymax)
                ymax = y[j];
            if (y[j] < ymin)
                ymin = y[j];
        }
        
        bool flag = true;
        for (int j = 0; j < points; j++){ 
            if (x[j] != xmax && x[j] != xmin && y[j] != ymin && y[j] != ymax){
                flag = false;
                break;
            }
        }
        if (!flag)
            cout << "NO" << endl;
        else cout << "YES" << endl;
    }
    return 0;
}