#include <vector>
#include <iostream>
#include <algorithm>

int main() {
    int testCount{};
    std::cin >> testCount;
    
    for (int k = 0; k < testCount; ++k) {
        int n{};
        std::cin >> n;
        std::vector<std::pair<int, int>> coord(n);
        std::pair<int, int> a(std::numeric_limits<int>::max(), std::numeric_limits<int>::max());
        std::pair<int, int> b(-std::numeric_limits<int>::max(), -std::numeric_limits<int>::max());
        
        for (int i = 0; i < n; ++i) {
            std::cin >> coord[i].first >> coord[i].second;
            a.first = std::min(a.first, coord[i].first);
            a.second = std::min(a.second, coord[i].second);
            b.first = std::max(b.first, coord[i].first);
            b.second = std::max(b.second, coord[i].second);
        }
        
        bool valid = true;
        
        for (int i = 0; valid && i < n; ++i) {
            valid = !(coord[i].first > a.first && coord[i].first < b.first
                       && coord[i].second > a.second && coord[i].second < b.second);
        }
        
        std::cout << (valid ? "YES\n" : "NO\n");
    }
    return 0;
}