#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,n;
    cin>>q;
    while(q--){
        cin>>n;
        int x,y,a[10][2],b[2],flag=0,h1=100000,h2=-100000,w1=100000,w2=-100000;
        for(int i=0;i<n;i++)
        {
            cin>>a[i][0]>>a[i][1];
            h1=min(h1,a[i][0]);
            h2=max(h2,a[i][0]);
            w1=min(w1,a[i][1]);
            w2=max(w2,a[i][1]);
        }
        for(int i=0;i<n;i++)
        {   
            if(!(a[i][0]==h1||a[i][0]==h2||a[i][1]==w1||a[i][1]==w2))
                flag=1;                                
        }
        if(flag==0)
            cout<<"YES\n";
        else
            cout<<"NO\n";
    }
    return 0;
}