#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 */  
    int q;
    cin >> q;
    for (int g = 0; g < q; g++)
    {
        int n;
        cin >> n;
        vector<int> x(n), y(n);
        for (int i = 0; i < n; i++)
            cin >> x[i] >> y[i];
        int minx = x[0], maxx = x[0], miny = y[0], maxy = y[0];
        
        for (int i = 1; i < n; i++)
        {
            if (x[i] > maxx)
                maxx = x[i];
            if (x[i] < minx)
                minx = x[i];
            if (y[i] > maxy)
                maxy = y[i];
            if (y[i] < miny)
                miny = y[i];
        }
        bool B = true;
        for (int i = 0; i < n; i++)   
          if (x[i] < maxx && x[i] > minx && y[i] < maxy && y[i] > miny)
            B = false;
        if (B)
            cout << "YES" << endl;
        else
            cout << "NO" << endl;
            
        
    }
    
    return 0;
}