#include <stdio.h>

int choose(int n, int k)
{
	printf("choose called for %d and %d\n", n, k);
	if ((k == 0) || (n == k))
		return 1;
	return choose(n - 1, k) + choose(n - 1, k - 1);
}

int main()
{
	int n, k;
	scanf("%d", &n);
	scanf("%d", &k);
	printf("%d choose %d is %d\n", n, k, choose(n, k));
}