#include <bits/stdc++.h>
using namespace std;
int main()
{
    int n;
    scanf("%d", &n);
    long long x = 1;
    for (int i = 2; i <= n; i++)
    {
        x *= i;
        while (x % 10 == 0)
            x /= 10;
        x %= 100000000;
    }
    printf("%lld", x % 10);
    return 0;
}