#include <stdio.h>

void rdump(int arr[],int len)

{

    int i = ;

    for(i=len-;i >= ; --i)

    {

        printf("%d",arr[i]);

    }

    printf("\n");

}

void trailingZeroes(int n) {

    int arr[] = {},len = ,i = ,j = ,c = ,d = ;

    for(i=; i <= n; ++i)

    {

        for(j = ; j < len; ++j)

        {

            d = arr[j] * i + c;

            arr[j] = d % ;

            c = d / ;

        }

        for(; c > ; c /= )

        {

            arr[len++] = c % ;

        }

    }

    rdump(arr,len);

}

int main()

{

    int n = ;

    while()

    {

        scanf("%d",&n);

        trailingZeroes(n);

    }

    return ;

}