#include <bits/stdc++.h>

using namespace std;

const int N = 11;
int x[N], y[N];

int main() {
  int q;
  scanf("%d", &q);
  while (q--) {
    int n;
    scanf("%d", &n);
    int max_x = INT_MIN, min_x = INT_MAX;
    int max_y = INT_MIN, min_y = INT_MAX;
    for (int i = 0; i < n; ++i) {
      scanf("%d %d", x + i, y + i);
      max_x = max(max_x, x[i]);
      max_y = max(max_y, y[i]);
      min_x = min(min_x, x[i]);
      min_y = min(min_y, y[i]);
    }
    bool check = true;//min_x != max_x && min_y != max_y;
    for (int i = 0; i < n; ++i) {
      check &= (x[i] == min_x || x[i] == max_x) || (y[i] == min_y || y[i] == max_y);
    }
    puts(check ? "YES" : "NO");
  }
  return 0;
}