#include <stdio.h>

int fact(int n)
{
	printf("factorial of %d called\n", n);
	if ((n == 1) || (n == 0))
		return 1;

	return n * fact(n - 1);
}

int main()
{
	int n;
	scanf("%d", &n);

	printf("Factorial = %d\n", fact(n));
}