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

int main() {
       int t;
    scanf("%d",&t);
    while(t--){
        int n;
        scanf("%d",&n);
        int x[10],y[10],i,min,max=0;
        int xmax=-10000,ymax = -10000,xmin = 10000 ,ymin=10000;
        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];
        }
        int f=0;
       for (i=0;i<n;i++)
           if ((x[i] != xmax) &&  (x[i] != xmin) &&  (y[i] != ymax) && (y[i] != ymin)){
                f=1;
                break;
           }
    if (f == 0){
        printf ("YES\n");
    }
    else
        printf ("NO\n");
        
    }
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */    
    return 0;
}