N = input()
K = int(input())

if int(N) < K:
  print(0)
  exit()

keta = []
for k in range(len(N)):
  keta.append(int(N[-k-1]))
ans = [1, keta[0], 0, 0];

def combination(N,K):
  if N < K:
    return 0
  else:
    p = 1
    for k in range(K):
      p *= N
      N -= 1
    for k in range(1, K+1):
      p //= k
    return p
for k in range(1, len(N)-1):
  if keta[k] > 0:
    a = [1, 0, 0, 0]
    for j in range(1, 4):
      a[j] += (9**(j))*combination(k, j)
      a[j] += (keta[k]-1)*combination(k, j-1)*(9**(j-1)) + ans[j-1]
    ans = [] + a
answer = (9**(K))*combination(len(N)-1, K)
answer += (keta[-1]-1)*(9**(K-1))*combination(len(N)-1, K-1)
answer += ans[K-1]
print(answer)