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

typedef struct
{
    int x;
    int y;
}pair_t;

int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    int Q;
    cin >> Q;
    for(int q=0;q<Q;q++)
    {
        int n;
        cin >> n;
        vector<pair_t> vec(n);
        int max_x = -10000;
        int min_x = 10000;
        int max_y = -10000;
        int min_y = 10000;
        for(int i=0;i<n;i++)
        {
            pair_t p;
            cin >> p.x >> p.y;
            if(max_x<p.x) max_x = p.x;
            if(min_x>p.x) min_x = p.x;
            if(max_y<p.y) max_y = p.y;
            if(min_y>p.y) min_y = p.y;
            vec[i] = p;
        }
        bool v = true;  // all points on the edge
        for(int i=0;i<n;i++)
        {
            pair_t p = vec[i];
            if( (min_x < p.x && p.x < max_x) &&
                (min_y < p.y && p.y < max_y) )
            {
                v = false;
                break;
            }
        }
        if(v)
            cout << "YES" << endl;
        else
            cout << "NO"  << endl;
    }
    return 0;
}