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


int main() {
    int X[12];
    int Y[12];
    int q, n;
    cin >> q;
    while (q --> 0) {
        cin >> n;
        
        int Xmax = -1000000;
        int Xmin = 1000000;
        int Ymax = -1000000;
        int Ymin = 1000000;
        
        for (int i=0; i<n; ++i) {
            cin >> X[i] >> Y[i];
            Xmax = max(Xmax, X[i]);
            Xmin = min(Xmin, X[i]);
            Ymax = max(Ymax, Y[i]);
            Ymin = min(Ymin, Y[i]);
        }
            
        bool success = true;
        for (int i=0; i<n; ++i) {
            int x = X[i], y = Y[i];
            if (x != Xmax && x != Xmin && y != Ymax && y != Ymin) {
                success = false;
                break;
            }
        }
        if (success) {
            cout << "YES" << endl;   
        } else {
            cout << "NO" << endl;
        }
    } 
    return 0;
}