#include <stdio.h>
#include <bits/stdc++.h>
using namespace std;
 

#define REP(i,n) for(int(i)=0;(i)<(int)(n);(i)++)

#include <vector>
#include <utility>


#include <algorithm>


int n,t;
int seen[110];
int x[110], y[110];

void solve() {
	for (scanf("%d", &t); t; t--) {
		scanf("%d", &n);
		REP(i,n) {
			seen[i] = 0;
			scanf("%d %d", &x[i], &y[i]);
		}

		int maxx = x[0], minx = x[0], maxy = y[0], miny = y[0];
		REP(i,n) {
			maxx = max(maxx, x[i]);
			minx = min(minx, x[i]);
			maxy = max(maxy, y[i]);
			miny = min(miny, y[i]);
		}

		bool ok = true;
		REP(i,n) {
			if (x[i] == minx || x[i] == maxx || y[i] == miny || y[i] == maxy) {}
			else ok = false;
		}

		printf("%s\n", ok ? "YES" : "NO");
	}
}


int main() {
    solve();
}