import copy
n = input()
k = int(input())

n_list = []
for a in n:
    n_list.append(int(a))
n_num = len(n_list)

dp = [[0] * 2 for _ in range(n_num + 1)]
dp[0][0] = 1
for i in range(n_num):
    nxt = [[0] * 2 for _ in range(n_num + 1)]
    for j in range(n_num):
        for l in range(2):
            lim = 9 if l else n_list[i]
            for x in range(lim + 1):
                if x != 0:
                    ns = j + 1
                else:
                    ns = j
                nlt = l | (x < n_list[i])
                nxt[ns][nlt] += dp[j][l]
    dp = copy.deepcopy(nxt)
ans = dp[k][0] + dp[k][1]
print(ans)