import sys
import math

input = sys.stdin.readline
n = int(input())
k = int(input())
t = n
m = 0
while t:
    m += 1
    t //= 10

def comb(n, r):
    if r > n:
        return 0
    return math.factorial(n) // (math.factorial(n - r) * math.factorial(r))

def dfs(i, mt, kt):
    a = i // 10 ** mt
    b = n // 10 ** mt
    if kt < 0:
        return 0
    if mt < kt:
        return 0
    if a < b:
        if mt > 0:
            return 9 ** kt * comb(mt, kt)
    elif a > b:
        return 0
    if i == n and kt == 0:
        return 1
    elif i > n:
        return 0
    ret = 0
    for j in range(10):
        f = 0
        if j != 0:
            f = 1
        ret += dfs(i+j*10**(mt-1), mt-1, kt-f)
    return ret

ans = dfs(0, m, k)
print(ans)
