N = input()
L = len(N)
K = int(input())
if L < K:
    print(0)
else:

    def main(d, k):
        if N[d] == "0":
            return main(d + 1, k)
        if (L - d) < k:
            return 0
        if k == 1:
            return ((L - d) - 1) * 9 + int(N[d])
        elif k == 2:
            return (
                ((((L - d) - 1) * ((L - d) - 2)) // 2) * 81
                + ((L - d) - 1) * 9 * (int(N[d]) - 1)
                + main(d + 1, k - 1)
            )
        elif k == 3:
            return (
                ((((L - d) - 1) * ((L - d) - 2) * ((L - d) - 3)) // 6) * (9 ** 3)
                + ((((L - d) - 1) * ((L - d) - 2)) // 2) * 81 * (int(N[d]) - 1)
                + main(d + 1, k - 1)
            )

    print(main(0, K))

