#include <bits/stdc++.h>
using namespace std;
#define sz(x) ((int) (x).size())
#define forn(i,n) for (int i = 0; i < int(n); ++i)
typedef long long ll;
typedef long long i64;
typedef long double ld;
const int inf = int(1e9) + int(1e5);
const ll infl = ll(2e18) + ll(1e10);

void solve() {
    int n;
    cin >> n;
    int xl = inf, xr = -inf, yl = inf, yr = -inf;
    vector<pair<int, int>> p;
    forn (i, n) {
        int x, y;
        cin >> x >> y;
        xl = min(xl, x);
        xr = max(xr, x);
        yl = min(yl, y);
        yr = max(yr, y);
        p.emplace_back(x, y);
    }
    for (auto v: p) {
        if (v.first == xl || v.first == xr)
            continue;
        if (v.second == yl || v.second == yr)
            continue;
        cout << "NO\n";
        return;
    }
    cout << "YES\n";
}

int main() {
    #ifdef LOCAL
    assert(freopen("b.in", "r", stdin));
    #else
    #endif
    int q;
    cin >> q;
    forn (i, q)
        solve();
}