#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

const int inf = 100005;

int main() {
    int q, n, x, y;
    cin >> q;
    while (q--) {
        cin >> n;
        int minX = inf, maxX = -inf, minY = inf, maxY = -inf;
        vector<pair<int, int> > points;
        while (n--) {
            cin >> x >> y;
            minX = min(minX, x);
            minY = min(minY, y);
            maxX = max(maxX, x);
            maxY = max(maxY, y);
            points.push_back(make_pair(x, y));
        }
            bool ok = true;
            for (auto p : points) {
                if (p.first == minX || p.first == maxX) continue;
                if (p.second == minY || p.second == maxY) continue;
                ok = false;
                break;
            }
            puts(ok ? "YES" : "NO");
        
    }
    return 0;
}