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



void query()
{
	int n;
    cin >> n;
	vector<int> x(n);
	vector<int> y(n);
	bool test=true;
	int max_x=-1000000;
	int max_y=-1000000;
	int min_x=1000000;
	int min_y=1000000;
	
	for (int i=0;i<n;i++)
	{
		cin >> x[i];		
		if (x[i] > max_x) max_x=x[i];
		if (x[i] < min_x) min_x=x[i];
		cin >> y[i];	
		if (y[i] > max_y) max_y=y[i];
		if (y[i] < min_y) min_y=y[i];		
	}	
	for (int i=0;i<n;i++)
	{
		if (((x[i]!=max_x) && (x[i]!=min_x)) && ((y[i]!= max_y) && (y[i]!=min_y)))	// if not on border x
		{			
			test=false;
			break;
		}			
	}
	
	
	if (test)
	{
		cout << "YES\n";
	} else
	{
		cout << "NO\n";
	}
	
}

int main()
{
	int q;
	cin >> q;
	for (int i=0;i<q;i++)
	{
		query();
	}
	return 0;
}