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


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    int T;
    cin >> T;
    for(int i = 0; i < T; i++) {
        int N;
        bool fail = false;
        cin >> N;
        vector< pair<int,int> > a(N);
        
        int xMin = 1000000,yMin = 10000000, xMax = -1000000, yMax = -100000000;
        for(int j = 0; j < N; j++) {
            cin >> a[j].first >> a[j].second;
            xMin = min(xMin,a[j].first);
            yMin = min(yMin,a[j].second);
            xMax = max(xMax,a[j].first);
            yMax = max(yMax,a[j].second);
        }
        for(int j = 0; j < N; j++) {
            if(a[j].first != xMin && a[j].first != xMax && a[j].second != yMin && a[j].second != yMax) {
                fail = true;
                break;
            }
        }
        if(fail) {
            cout << "NO\n";
        } else {
            cout << "YES\n";
        }
    }
    return 0;
}