#include <algorithm>
#include <iomanip>
#include <istream>
#include <map>
#include <numeric>
#include <ostream>
#include <set>
#include <sstream>
#include <string>
#include <utility>
#include <vector>

using namespace std;


class Solution {
public:
    void solve(std::istream& in, std::ostream& out) {
		int q; in >> q;

		for (int i = 0; i < q; i++)
		{
			int n; in >> n;

			vector<pair<int, int>> points;

			set<int> xs;
			set<int>ys;

			for (int j = 0; j < n; j++)
			{
				double x, y; in >> x >> y;
				xs.insert(x);
				ys.insert(y);
				points.push_back({ x,y });
			}

			if (n == 1 || n == 2)
			{
				out << "YES" << endl;
				continue; 
			}
			else
			{
				if (xs.size() == 1 || ys.size() == 1)
				{
					out << "NO" << endl;
					continue;
				}

				bool is_ok = true;

				for (int j = 0; j < n; j++)
				{
					int x = points[j].first; int y = points[j].second;

					for (int k = 0; k < n; k++)
					{
						if (j == k)
							continue;
						for (int l = 0; l < n; l++)
						{
							if (j == l)
								continue;

							int x1 = points[k].first; int y1 = points[k].second;
							int x2 = points[l].first; int y2 = points[l].second;

							if (x > min(x1, x2) && x < max(x1, x2) && y > min(y1, y2) && y < max(y1, y2))
							{
								is_ok = false;
								break;
							}
						}

						if (!is_ok)
							break;
					}

					if (!is_ok)
						break;
				}

				if (is_ok) {
					out << "YES" << endl;
					continue;
				}

			}

			out << "NO" << endl;


		}

    }
};

void solve(std::istream& in, std::ostream& out)
{
    out << std::setprecision(12);
    Solution solution;
    solution.solve(in, out);
}


#include <fstream>
#include <iostream>


int main() {
    
    ios_base::sync_with_stdio(0);
    cin.tie(0);


    istream& in = cin;


    ostream& out = cout;

    solve(in, out);
    return 0;
}