n = str(input())
k = int(input())
dp = [[[0 for i in range(len(n)+1)] for i in range(2)] for i in range(len(n)+1)]
dp[0][0][0] = 1
for a in range(len(n)):
  for b in range(2):
    for c in range(len(n)):
      for i in range(10):
        if b ==1:
          if i != 0:
            dp[a+1][1][c+1] += dp[a][1][c]
          else:
            dp[a+1][1][c] += dp[a][1][c]
        else:
          if int(n[a]) > i and i ==0:
            dp[a+1][1][c] += dp[a][0][c]
          if int(n[a]) > i and i != 0:
            dp[a+1][1][c+1] += dp[a][0][c]
          if int(n[a]) == i and i ==0:
            dp[a+1][0][c] += dp[a][0][c]
          if int(n[a]) == i and i !=0:
            dp[a+1][0][c+1] += dp[a][0][c]
print(dp[-1][0][k] + dp[-1][1][k])           
