#include <bits/stdc++.h>
#define ll unsigned long long
using namespace std;
struct node
{
	int a,b;
} arr[50] ;
int main()
{
   //freopen("in.txt","r",stdin);
     int q;
     cin>>q;
     while(q--)
     {
     	int n;cin>>n;
     	 int xmax=-1000000,xmin=100000,ymax=-1000000,ymin=10000000;
		map<int,int> m ;
		for(int i=0;i<n;i++)
     	{
     		cin>>arr[i].a>>arr[i].b;
     	    if(arr[i].a <xmin)
			  xmin=arr[i].a;
	     	 if(arr[i].a >xmax)
	  		  xmax=arr[i].a;
	    	 if(arr[i].b <ymin)
	 		  ymin=arr[i].b;
	      	 if(arr[i].b >ymax)
			  ymax=arr[i].b;
     	}
     	int p=0,q=0,r=0,s=0;
         for(int i=0;i<n;i++)
		 {
		 	if(arr[i].a==xmax)
		 	  p++;
		 	else if(arr[i].a==xmin)
		 	  q++;
		 	else if(arr[i].b==ymax)
		 	  r++;
		 	else if(arr[i].b==ymin)
		 	  s++;
		 	
 		 }   	
          if(p+q+r+s==n)
		   cout<<"YES";
		   else cout<<"NO";
		   cout<<endl;    	
     }

      return 0;
}