//
//  main.cpp
//  HackerRank-101Hack42
//
//  Created by BahadirAltun on 18/10/16.
//  Copyright © 2016 Bahadir Altun. All rights reserved.
//

#include <algorithm>
#include <iostream>
#include <cassert>
#include <climits>
#include <cstdlib>
#include <cstring>
#include <cstdio>
#include <string>
#include <vector>
#include <cmath>
#include <ctime>
#include <queue>
#include <stack>
#include <map>
#include <set>

using namespace std;

#define mid ((lf + rg) >> 1)
#define right (left | 1)
#define left (v << 1)

typedef pair<long long, long long> pii;
typedef long long ll;

const ll linf = 1e18 + 9;
const long long inf = 1e9 + 9;
const long long N = 3e5 + 9;

int q, n;
ll a[N], b[N];

int main() {

  cin >> q;

  for (int qq = 1; qq <= q; qq++) {
    cin >> n;
    for (int i = 1; i <= n; i++) cin >> a[i] >> b[i];
    int mxx, mnx, mxy, mny;
    mxx = mnx = mxy = mny = 1;
    for (int i = 1; i <= n; i++) {
      if (a[mxx] < a[i]) mxx = i;
      if (a[mnx] > a[i]) mnx = i;
      if (b[mxy] < b[i]) mxy = i;
      if (b[mny] > b[i]) mny = i;
    }
    bool flag = 0;
    for (int i = 1; i <= n; i++)
      if (a[i] != a[mxx] and a[i] != a[mnx] and b[i] != b[mny] and b[i] != b[mxy]) flag = 1;
    if (flag) puts("NO");
    else puts("YES");
  }

  return 0;
}