#include <stdio.h>

int factorial(int n)
{
	int r;

	printf("enter (n=%d)\n", n);

	if (n == 0) {
		r = 1;
	} else {
		r = n * factorial(n-1);
	}

	printf("exit (n=%d, r=%d)\n", n, r);

	return r;
}

int main(void)
{
	printf("%d\n", factorial(10));

	return 0;
}