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()
  res = sum(map(int, N))
  res = max(res, max(0, int(N[0]) - 1 + 9 * (len(N) - 1)))
  for i in range(1, len(N) - 1):
      if int(N[i]) > 0:
          t = 0
          for j in range(i):
              t += int(N[j])
          t += int(N[i]) - 1 + 9 * (len(N) - i - 1)
          res = max(res, t)
  print(res)
  
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"}]