#include <bits/stdc++.h>

#define ll long long
#define f first
#define s second
#define pb push_back

using namespace std;

const int N = 12;
const int mod = 1e9;
int q, n;

pair < int, int > a[N];

void solve()
{
  cin >> n;
  int mn = mod, mx = -mod;
  for (int i = 0;i < n;i++)
  {
    cin >> a[i].f >> a[i].s;
    mx = max(mx, a[i].s);
    mn = min(mn, a[i].s);
  }
  sort(a, a + n);
  if (a[0].f == a[n - 1].f || mx == mn)
  {
    cout << "YES\n";
    return;
  }
  for (int i = 0;i < n;i++)
  {
    if (a[i].f == a[0].f || a[i].f == a[n - 1].f)
    {
      continue;
    }
    if (a[i].s == mn || a[i].s == mx) continue;
    cout << "NO\n";
    return;
  }
  cout << "YES\n";
}
int main()
{
  #ifdef wws
    freopen("in", "r", stdin);
  #endif // wws
  cin >> q;
  while(q--)
  {
    solve();
  }
  return 0;
}