#include<stdio.h>
int main()
{
    int n;
    scanf("%d",&n)
    if(n==0)
    {
        sum=0;
    }
    else
    {
        while(n>0)
        {
            x=n%10;
            sum=sum*x
            x=n/10;
        }
        printf("%d",sum)
    }
    return 0;
}