#include <stdio.h>
#include <stdlib.h>

int main(void)
{
	printf("%d\n", f(5));
	printf("%d\n", f(5.4));
	return 0;
}

int f(int n)
{
	fprintf(stderr, "%d\n", n);
	if (n<=0)
		return 1;
	else
		return n*f(n-1);
}