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


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    long long x1, x2, y1, y2, n, q, i;
    cin >> q;
    while(q--) {
        cin >> n;
        long long x[n], y[n];
        bool flag=true;
        for(i=0; i<n; ++i) {
            cin >> x[i] >> y[i];
        }
        x1 = x[0];
        y1 = y[0];
        x2 = x1;
        y2 = y1;
        for(i=0; i<n; ++i) {
            if(x[i] < x1) {
                x1 = x[i];
            }
            if(x[i] > x2) {
                x2 = x[i];
            }
            
            if(y[i] < y1) {
                y1 = y[i];
            }
            if(y[i] > y2) {
                y2 = y[i];
            }
        }
        
        for(i=0; i<n; ++i) {
            if(x[i] > x1 && x[i] < x2 && y[i] > y1 && y[i] < y2)
                flag = false;
        }
        
        if(flag)
            cout << "YES\n";
        else
            cout << "NO\n";
    }
    return 0;
}