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: n = input().zfill(16)
  INF = 10**18
  memo_ls = [[0 for i in range(2)] for j in range(17)]
  memo_ls[0][0] = 0
  memo_ls[0][1] = -INF
  for i in range(1, 17):
      s = int(n[i - 1])
      memo_ls[i][0] = memo_ls[i - 1][0] + s
      memo_ls[i][1] = memo_ls[i - 1][1] + 9
      if s > 0:
          memo_ls[i][1] = max(memo_ls[i][1], memo_ls[i - 1][0] + s - 1)
  print(max(memo_ls[-1]))
  
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"}]