#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>
#define mod 1000000007

 void merge(int A[ ] , int start, int mid, int end) {
int p = start ,q = mid+1;
int Arr[end-start+1] , k=0;
    for(int i = start ;i <= end ;i++){
        if(p > mid) Arr[ k++ ] = A[ q++] ;
        else if ( q > end) Arr[ k++ ] = A[ p++ ];   
        else if( A[ p ] < A[ q ]) Arr[ k++ ] = A[ p++ ];    
        else  Arr[ k++ ] = A[ q++];     
     }
   for (int p=0 ; p< k ;p ++) {  
       A[ start++ ] = Arr[ p ] ;                          
  }
}
   void merge_sort (int A[ ] , int start , int end ){
  
           if( start < end ) {
               int mid = (start + end ) / 2 ;           
               merge_sort (A, start , mid ) ;               
               merge_sort (A,mid+1 , end ) ;         
               merge(A,start , mid , end );   
           }                    
   }

int main() {
    int t,n,x[12],y[12];
    scanf("%d",&t);
     while(t>0){
        t--;
        scanf("%d",&n);
         int max=0,min=mod;
         for(int i=0;i<n;i++){
            scanf("%d %d",&x[i],&y[i]);
         } 
         merge_sort (x , 0 , n-1 );
         merge_sort (y , 0 , n-1 );
         int cnt=0,cnt1=0,cnt2=0;
         for(int i=0;i<n-2;i++){
             //if(((x[i]<=x[n-1]&&x[i]>=x[0])&&(y[i]==y[n-1]||y[i]==y[0]))||((y[i]<=y[n-1]&&y[i]>=y[0])&&(x[i]==x[n-1]||x[i]==y[0])))continue;
             if(x[i]<=x[n-1]&&x[i]>=x[0]){
                 if(y[i]==y[n-1]||y[i]==y[0])continue;
                 else{ cnt++;break;}
             }
            else if(y[i]<=y[n-1]&&y[i]>=y[0]){
                 if(x[i]==x[n-1]||x[i]==y[0])continue;
                else {cnt1++;break;}
             }   
             else{
                 cnt2++;
                 break;
             }
        
         }
         if(cnt2>0||cnt1>0||cnt>0)printf("NO\n");
         else printf("YES\n");
         
    }
   // printf("YES");

    /* Enter your code here. Read input from STDIN. Print output to STDOUT */    
    return 0;
}