n = input()
k = int(input())
ln = len(n) + 1

dp=[[[0]* (ln) for _ in range(2)] for i in range(ln)]
dp[0][0][0] = 1
for i in range(len(n)):
  for smaller in range(2):
    x = int(n[i])
    t = 9 if smaller else x
    for j in range(t+1):
      for knum in range(ln-1):
        if j == 0:
          dp[i+1][int(smaller or j < x)][knum] += dp[i][smaller][knum]
        else:
          dp[i+1][int(smaller or j < x)][knum+1] += dp[i][smaller][knum]
try:
  print(dp[-1][0][k] + dp[-1][1][k])
except:
  print(0)