#pragma region Header
#include <climits>
#include <map>
#include <queue>
#include <iomanip>
#include <cstdlib>
#include <functional> 
#include <unordered_map>
#include <unordered_set>
#include <stdio.h>
#include <ctime>
#include <stack>
#include <sstream>
#include <fstream>
#include <vector>
#include <string>
#include <algorithm>
#include <set>
#include <iostream>

#define ft first
#define sc second

#define X first
#define Y second

#define mp make_pair

#define All(x) (x).begin(),(x).end()
#define rAll(x) (x).rbegin(),(x).rend()
typedef long long ll;
typedef long double ld;
using namespace std;

ld PI = acos(-1);

template<class T>inline const T sqr(const T & x) { return x*x; }
ll popcnt(ll mask) { ll cnt = 0; while (mask) cnt += mask & 1, mask >>= 1; return cnt; }
ll powi(ll a, ll b, ll mod = 1000000007) { if (b < 2) return b ? a : 1; return (powi((a*a) % mod, b / 2, mod)*(b % 2 ? a : 1LL)) % mod; }
ll mod7 = 1000000007; ll mod9 = 1000000009;
bool isprime(ll n) { if (n < 2) return 0; for (ll i = 2; i*i <= n; i++) if (n%i == 0) return 0; return 1; }
#pragma endregion

int main() {
#ifdef _DEBUG
	ifstream cin("input.txt");
#endif
	int q;
	cin >> q;
	while(q--)
	{
		int n,x,y;
		map<int, set<int>> a;
		map<int, set<int>> b;

		cin >> n;
		int mnx = 1e9;
		int mny = 1e9;
		int mxx = -1e9;
		int mxy = -1e9;
		vector<pair<int, int>> v;
		for(int i=0;i<n;i++)
		{
			cin >> x >> y;
			v.push_back({ x,y });
			mnx = min(mnx, x);
			mny = min(mny, y);

			mxx = max(mxx, x);
			mxy = max(mxy, y);

		}
		bool flag = true;
		for(int i = 0;i<n;i++)
		{
			flag &= (v[i].X == mnx || v[i].Y == mny || v[i].X == mxx || v[i].Y == mxy);
		}
		cout << ((flag) ? "YES" : "NO");
		cout << endl;
	}

	
#ifdef _DEBUG
	system("pause");
	//	cin.get(); cin.get();
#endif
	return 0;
}