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


int main() {
    int q;
    cin >> q;
    while (q-->0){
        int n;
        cin >> n;
        vector<int> X(n), Y(n);        
        for (int i = 0; i < n; i++){
            cin >> X[i] >> Y[i];
        }
        int min_x = *min_element(X.begin(), X.end());
        int max_x = *max_element(X.begin(), X.end());
        int min_y = *min_element(Y.begin(), Y.end());
        int max_y = *max_element(Y.begin(), Y.end());
        bool can = true;
        for (int i = 0; i < n; i++){
            bool ok = 
                (X[i] == min_x || X[i] == max_x) ||
                (Y[i] == min_y || Y[i] == max_y);
            if (!ok){
                can = false;
                break;
            }
        }
        cout << (can ? "YES" : "NO") << endl;
    }
    return 0;
}