#include <cstdio>
#include <iostream>
#include <algorithm>
#define MAXN 1010
#define fi first
#define se second
using namespace std;
typedef pair<int, int> ii;

ii ar[MAXN];
ii rev[MAXN];
int n;
int q;
char ans[2][10] = {"YES", "NO"};

int f() {
	sort(ar + 1, ar + n + 1);		
	sort(rev + 1, rev + n + 1);

	int temp = 2;
	int x1 = ar[1].fi;
	int x2 = ar[n].fi; 
	int y1 = rev[1].fi;
	int y2 = rev[n].fi;

//	if(x2 == x1 || y2 == y1)
//		return 1;

	for(int i = 1; i <= n; i++) {
		if((ar[i].fi == x1 || ar[i].fi == x2) && ar[i].se >= y1 && ar[i].se <= y2)
			continue;
		if((ar[i].se == y1 || ar[i].se == y2) && ar[i].fi >= x1 && ar[i].fi <= x2)
			continue;
		return 1;
	}

	return 0;
}

int main() {
	cin >> q;
	for(int t = 0; t < q; t++) {
		cin >> n;
		for(int i = 1; i<= n; i++) {
			cin >> ar[i].fi >> ar[i].se;
			rev[i] = ii(ar[i].se, ar[i].fi);
		}

		printf("%s\n", ans[f()]);
	}
	return 0;
}