#include <bits/stdc++.h>

using namespace std;

const int INF = 1e5;

int main() {
    int q;
    cin >> q;
    while (q--) {
        int n;
        cin >> n;
        vector<int> x(n), y(n);
        int minX = INF, minY = INF;
        int maxX = -INF, maxY = -INF;
        for (int i = 0; i < n; ++i) {
            cin >> x[i] >> y[i];
            minX = min(minX, x[i]);
            minY = min(minY, y[i]);
            maxX = max(maxX, x[i]);
            maxY = max(maxY, y[i]);
        }

        bool yes = true;
        for (int i = 0; i < n; ++i) {
            if ((x[i] != minX && x[i] != maxX) && (y[i] != minY && y[i] != maxY)) {
                yes = false;
                break;
            }
        }

        if (yes) {
            cout << "YES\n";
        } else {
            cout << "NO\n";
        }
    }
    return 0;
}