#include <iostream>
#include <string>
using namespace std;

int main()
{
	int n;
	cin >> n;
	long long m = 1;
	for (int i = 1; i <= n; i++)
	{
		m *= i;
		while (m % 10 == 0)
		{
			m /= 10;
		}
	}
	cout << m % 10;
	cin.get();
	cin.get();
	return 0;
}