import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
sys.setrecursionlimit(10 ** 7)

from functools import lru_cache

n, k = map(int, read().split())


@lru_cache(None)
def check(n, k):
    a, b = divmod(n, 10)
    cnt = 0
    if k >= 1:
        cnt += check(a, k - 1) * b
        cnt += check(a - 1, k - 1) * (9 - b)
    cnt += check(a, b)
    return cnt


if n < 10:
    if k == 1:
        print(n)
    else:
        print(0)
else:
    print(check(n, k))
