#define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES
//libs
#include <iostream>
#include <algorithm>
#include <set>
#include <vector>
#include <string>
#include <map>
#include <complex>
#include <fstream>
#include <iomanip>
#include <cmath>
#include <queue>

using namespace std;
//defines
#define infll 8e18
#define ll long long
#define itn ll
#define vi vector<itn>
#define vvi vector<vi>
#define pii pair<itn,itn> 
//constants
const double eps = 1e-7;
const ll mod = 1000000007;
//end of definition

struct pt
{
	int x, y;
	pt(){}
};

void solve()
{
	int n;
	cin >> n;
	vector<pt> a(n);
	for (int i = 0; i < n; i++)
		cin >> a[i].x >> a[i].y;
	set<int> allx, ally;
	pt slx, sly;
	int minx = 1e9, maxx = -1e9, miny = 1e9, maxy = -1e9;

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


	cout << "YES\n";
}

int main()
{
	ios_base::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);
#ifdef _DEBUG
	freopen("input.txt", "r", stdin);
	//freopen("input.txt", "w", stdout);
#endif
	int n;
	cin >> n;
	for (int i = 0; i < n;i++)
		solve();

	return 0;
}