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

int main() {

    /* Enter your code here. Read input from STDIN. Print output to STDOUT */ 
    int q;
    scanf("%d",&q);
    while(q--){
        
        int n,flag=0;
        scanf("%d",&n);
        int a[n],b[n];
        for(int i=0;i<n;i++){
            scanf("%d %d",&a[i],&b[i]);
        }
        for(int i=0;i<n;i++){
            int count_a=0,count_b=0;
            flag=0;
            for(int j=0;j<n;j++){
                if(i!=j){
                    if(a[i]!=a[j])count_a++;
                    if(b[i]!=b[j])count_b++;
                }
            }
            if(count_a==n-1 && count_b==n-1)flag=1;
        }
        if(flag==0)printf("YES\n");
        else printf("NO\n");
        
    }
    return 0;
}