#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 t;
    cin>>t;
    while(t--)
    {
        int n;
        cin>>n;
        vector<int> x(n,0);
        vector<int> y(n,0);
        for(int i(0);i<n;i++)
            cin>>x[i]>>y[i];
        
        int min_x = *min_element(x.begin(),x.end());
        int min_y = *min_element(y.begin(),y.end());
        int max_x = *max_element(x.begin(),x.end());
        int max_y = *max_element(y.begin(),y.end());
        int f = 0;
        //cout<<min_x<<max_x<<min_y<<max_y<<endl;
        
        for(int i(0);i<n;i++)
        {
            if(!(x[i] == min_x || x[i] == max_x || y[i] == max_y || y[i] == min_y))
            {
                f = 1;
                break;
            }
        }
        if(f==1) cout<<"NO"<<endl;
        else cout<<"YES"<<endl;
    }
    return 0;
}