#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vll;
typedef pair<int, int> pii;
typedef vector<pii> vii;
typedef vector<bool> vb;
typedef vector<string> vs;
#define x first
#define y second

int main() {
	ios::sync_with_stdio(false), cin.tie(0);
	int t; cin >> t;
	while (t--)
	{
		int n; cin >> n;
		vii p(n);
		int mxx = -100000, mnx = 100000, mxy = -100000, mny = 100000;
		for (int i = 0; i < n; i++)
		{
			cin >> p[i].x >> p[i].y;
			mnx = min(mnx, p[i].x);
			mny = min(mny, p[i].y);
			mxx = max(mxx, p[i].x);
			mxy = max(mxy, p[i].y);
		}
		bool w = false;
		for (int i = 0; i < n; i++)
			if (!(p[i].x == mnx || p[i].x == mxx || p[i].y == mny || p[i].y == mxy))
			{
				w = true;
				break;
			}
		cout << (w ? "NO" : "YES") << endl;
	}
	//cin.ignore(), cin.get();
}