#include <stdio.h>

int comb(int a, int b)
{
	if (b == 0 || b == a) {
		return 1;
	}
	return comb(a - 1, b) + comb(a - 1, b - 1);
}

int main()
{
	int a, b;

	printf("a b\n");
	scanf("%d%d", &a, &b);
	printf("comb(%d, %d) = %d\n", a, b, comb(a, b));
	return 0;
}