#include <stdio.h>
#include <math.h>
#include <string.h>
int main()
{
    int n,t=10;
    while(t--)
    {
        scanf("%d",&n);
        int s=0,sum=0,y;
        if(n==0)
        {
            return 0;
        }
        while(n>=3)
        {
            s=n/3;
            sum+=s;
            y=n%3;
            n=s+y;
        }
      if(n==2)
       {
           sum++;
       }
        printf("%d\n",sum);
    }
    return 0;
}