#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 t,n;
        int a[10],cnt;
        scanf("%d",&t);
        while(t--)
        {
            int i,p,q;
            cnt=0;
            scanf("%d",&n);
            int a[n];
            for(i=0;i<n;i++)
            {
                scanf("%d %d",&p,&q);
                if(p==0 || q==0)
                {

                    cnt++;
                }


            }
            if(cnt==n)
                printf("YES\n");
            else
                printf("NO\n");
            a[i]=cnt;

        }
    return 0;
}