#include <bits/stdc++.h>
using namespace std;

void solve(){
	int n;
	cin >> n;

	vector<int> x(n), y(n);
	int maxx = -10000, minx = 10000, maxy = -10000, miny = 10000;
	for (int i = 0; i < n; i++) {
		cin >> x[i] >> y[i];
		maxx = max(maxx, x[i]);
		minx = min(minx, x[i]);
		maxy = max(maxy, y[i]);
		miny = min(miny, y[i]);
	}

	for (int i = 0; i < n; i++) {
		if (x[i] != maxx && x[i] != minx && y[i] != maxy && y[i] != miny) {
			cout << "NO";
			return;
		}
	}

	cout << "YES";
}

int main(){
	int t;
	cin >> t;
	while (t--) {
		solve();
		cout << endl;
	}
}