#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,x[11],y[11],minx,miny,maxx,maxy,i,j;
   
    cin>>q;
    for(i=0;i<q;i++)
        {
         minx=100000,miny=100000,maxx=-100000,maxy=-100000;
        cin>>n;
        for(j=0;j<n;j++)
            {
            cin>>x[j]>>y[j];
            if(x[j]<minx)
                {
                minx=x[j];
            }
            if(x[j]>maxx)
                {
                maxx=x[j];
            }
            if(y[j]<miny)
                {
                miny=y[j];
            }
            if(y[j]>maxy)
                {
                maxy=y[j];
            }
            
}
        for(j=0;j<n;j++)
            {
            if(x[j]==minx||x[j]==maxx||y[j]==miny||y[j]==maxy)
                {
               
                continue;
            }
            else{
                cout<<"NO"<<endl;
                break;
            }
        }
       if(j==n)
            {
            cout<<"YES"<<endl;
        }
    }
    return 0;
}