#include <stdio.h>
#include <string.h>

#define MAX	100
#define BN_MAX	1000

struct BigNum {
	int size;
	int sign;
	char num[BN_MAX];
};

typedef struct BigNum BigNum;

void bignum_2str(BigNum *a, char *s)
{
	int i;
	if (a->sign == -1)
		*s++ = '-';
	if (a->size == 0)
		*s++ = '0';
	for (i = a->size-1; i >= 0; i--)
		*s++ = a->num[i] + '0';
	*s = '\0';
}

void bignum_str2(char *s, BigNum *r)
{
	int i;
	r->sign = *s == '-' ? s++, -1 : 1;
	while (*s == '0' && *s != '\0')
		s++;
	r->size = strlen(s);
	for (i = r->size-1; i >= 0; i--)
		r->num[i] = (*s++) - '0';
}

void bignum_copy(BigNum *a, BigNum *r)
{
	r->sign = a->sign;
	r->size = a->size;
	memcpy(r->num, a->num, r->size);
}

void bignum_add(BigNum *a, BigNum *b, BigNum *r)
{
	int i, j, k, carry, tmp;
	
	if (a->sign == b->sign) {
		r->sign = a->sign;

		i = j = k = carry = 0;
		while (i < a->size || j < b->size || carry) {
			tmp = carry;
			carry = 0;
			tmp += i < a->size ? a->num[i++] : 0;
			tmp += j < b->size ? b->num[j++] : 0;
			if (tmp >= 10) {
				carry = 1;
				tmp -= 10;
			}
			r->num[k++] = tmp;
		}
		r->size = k;
	}
}

BigNum C[MAX+1][MAX+1];
char s[BN_MAX+1];

int main()
{
	int n, p;
	int i, j;

	bignum_str2("1", &C[0][0]);
	for (i = 1; i <= MAX; i++) {
		bignum_copy(&C[0][0], &C[i][0]);
		bignum_copy(&C[0][0], &C[i][i]);
		for (j = 1; j < i; j++)
			bignum_add(&C[i-1][j], &C[i-1][j-1], &C[i][j]);
	}

	for (;;) {
		scanf("%d %d", &n, &p);
		if (n == 0 && p == 0)
			break;
		bignum_2str(&C[n][p], s);
		printf("%d things taken %d at a time is %s exactly.\n", n, p, s);
	}

	return 0;
}