#include <stdio.h>

#include <stdlib.h>

int find(int s)

{

    int n = 0;

    scanf_s("%d",&s);

    int a[100] = { 213,432,5436,765324,243,654,12387,87626,645,625,5234,246 };

    for (int i = 0; i < 100; i++)

    {

        if (s == a[i])

        {

            return i;

            break;

        }

        else

            n++;

    }

    if (n == 100)

        return -1;

}

int main()

{

    while (1)

    {

        int m = find(0);

        printf_s("%d\n", m);

    }

    return 0;

}