#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>

int main() {
    int t;
     scanf("%d",&t);
    while(t--)
        {
 int x[100],y[100],i,j;
        int flag=0,count[100]={0},xmax=-10000,ymax=-10000,xmin=10000,ymin=10000;
    int n;
        scanf("%d",&n);
    for(i=0;i<n;i++)
        {
           scanf("%d%d",&x[i],&y[i]);
        if(xmax<=x[i])
            {
            xmax=x[i];
        }
        if(ymax<=y[i])
            {
            ymax=y[i];
        }
         if(xmin>=x[i])
            {
            xmin=x[i];
        }
        if(ymin>=y[i])
            {
            ymin=y[i];
        }
    }
    /*    printf("min%d",xmin);
         printf("max%d",xmax);
         printf("min%d",ymin);
         printf("max%d",ymax);*/
    for(i=0;i<n;i++)
        {
       
             if((x[i]!=xmin)&&(x[i]!=xmax)&&(y[i]!=ymin)&&(y[i]!=ymax))
                 {
              
                  flag=1; 
                 break;
                
             }
          else
              {
              flag=0;
              
          }
          
    }
    
    if(flag==1)
        {
         printf("NO");
    }
        else
            {
             printf("YES");
        }
       printf("\n");
       
    }
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */    
    return 0;
}