output_description: Print the maximum possible sum of the digits (in base 10) of a positive
  integer not greater than N.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N
attempt: # -*- coding: utf-8 -*-
  N = int(input())
  
  
  def Sum(n):
      s = str(n)
      array = list(map(int, list(s)))
      return sum(array)
  
  
  a = []
  
  a.append(Sum(N))
  
  N_str = str(N)
  N_str = list(map(int, list(N_str)))
  
  "右端の数字を1下げたときの最大"
  N_str = str(N)
  N_str = list(map(int, list(N_str)))
  N_str[0] = N_str[0] - 1
  for i in range(1, len(N_str)):
      N_str[i] = 9
  a.append(sum(N_str))
  
  print(max(a))
  
problem_description: Statement
  
  Find the maximum possible sum of the digits (in base 10) of a positive integer
  not greater than N.
samples: [{"input": "100", "output": "18\n    \n\nFor example, the sum of the digits in 99 is 18, which turns out to be the\nmaximum value.\n\n* * *"}, {"input": "9995", "output": "35\n    \n\nFor example, the sum of the digits in 9989 is 35, which turns out to be the\nmaximum value.\n\n* * *"}, {"input": "3141592653589793", "output": "137"}]