/*
*/

#pragma comment(linker, "/STACK:16777216")
#define _CRT_SECURE_NO_WARNINGS

#include <fstream>
#include <iostream>
#include <string>
#include <complex>
#include <math.h>
#include <set>
#include <vector>
#include <map>
#include <queue>
#include <stdio.h>
#include <stack>
#include <algorithm>
#include <list>
#include <ctime>
#include <memory.h>
#include <assert.h>

#define y0 sdkfaslhagaklsldk
#define y1 aasdfasdfasdf
#define yn askfhwqriuperikldjk
#define j1 assdgsdgasghsf
#define tm sdfjahlfasfh
#define lr asgasgash
#define norm asdfasdgasdgsd

#define eps 1e-9
#define M_PI 3.141592653589793
#define bs 1000000007
#define bsize 350

using namespace std;

const int INF = 1e9;
const int N = 200031;

int tests, n, x[N], y[N];
vector<int> xs, ys;
int flag;

bool lies_on_v(int x, int y, int x1, int y1, int y2)
{
	if (x != x1)
		return false;
	if (y<y1 || y>y2)
		return false;
	return true;
}

bool validate(int x1, int x2, int y1, int y2)
{
	if (x1 >= x2)
		return false;
	if (y1 >= y2)
		return false;
	for (int i = 0; i < n; i++)
	{
		if (lies_on_v(x[i], y[i], x1, y1, y2) || lies_on_v(x[i], y[i], x2, y1, y2) || lies_on_v(y[i], x[i], y1, x1, x2) || lies_on_v(y[i], x[i], y2, x1, x2))
			continue;
		return false;
	}
	return true;
}

int main(){
	//freopen("fabro.in","r",stdin);
	//freopen("fabro.out","w",stdout);
	//freopen("F:/in.txt", "r", stdin);
	//freopen("F:/output.txt", "w", stdout);
	ios_base::sync_with_stdio(0);
	//cin.tie(0);

	cin >> tests;
	for (; tests; --tests)
	{
		cin >> n;
		for (int i = 0; i < n; i++)
		{
			cin >> x[i] >> y[i];
		}
		xs.clear();
		ys.clear();
		xs.push_back(-100000);
		xs.push_back(100000);
		ys.push_back(-100000);
		ys.push_back(100000);
		for (int i = 0; i < n; i++)
		{
			xs.push_back(x[i]);
			ys.push_back(y[i]);
		}
		flag = 0;

		for (int i = 0; i < xs.size(); i++)
		{
			for (int j = 0; j < xs.size(); j++)
			{
				for (int q = 0; q < ys.size(); q++)
				{
					for (int w = 0; w < ys.size(); w++)
					{
						if (validate(xs[i], xs[j], ys[q], ys[w]))
							flag = 1;
					}
				}
			}
		}
		if (flag == 0)
			cout << "NO" << endl;
		else
			cout << "YES" << endl;
	}
	cin.get(); cin.get();
	return 0;
}