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

int main() 
{
    int q,a,b,i,count=0,p,j;
    
    scanf("%d",&q);
    
    for(i=0;i<q;i++)
    {
        scanf("%d",&p);
        
        for(j=0;j<p;j++)
        {
            scanf("%d %d",&a,&b);
            if(a == 0 || a ==1 )
                count++;
            if(b == 0 || b ==1 )
                count++;
        }
        
        if(count == (2*p))
            printf("YES \n");
        else
            printf("NO");
        
    }

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