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


long min(long a[],long n)
    {long min=10000;
    for(int i=0;i<n;i++)
        if(a[i]<min)
        min=a[i];
        return min;
}
long max(long a[],long n)
    {long max=-10000;
    for(int i=0;i<n;i++)
        if(a[i]>max)
        max=a[i];
        return max;
}

int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */  
    int flag=0;
    long x[10],y[10];
    long q,n,i,j,lowx,lowy,highx,highy;
    cin>>q;
    for(j=0;j<q;j++)
        {
    cin>>n;
    for(i=0;i<n;i++)
        cin>>x[i]>>y[i];
    lowx=min(x,n);
    highx=max(x,n);
    lowy=min(y,n);
    highy=max(y,n);
    for(i=0;i<n;i++)
        {
        if((x[i]==lowx)||(x[i]==highx)||(y[i]==lowy)||(y[i]==highy))
         {
            flag=1;
        }
        else
		{flag=0;
		break;
		 } 
        
    }
    if(flag==1)
cout<<"YES\n";
    else
        cout<<"NO\n";
    }
        return 0;
}