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: S = input()
  dp = [[0 for i in range(len(S))] for j in range(2)]
  dp[0][0] = int(S[0])
  dp[1][0] = int(S[0]) - 1
  for i in range(len(S) - 1):
      dp[0][i + 1] = dp[0][i] + int(S[i + 1])
      dp[1][i + 1] = max(dp[0][i] + int(S[i + 1]) - 1, dp[1][i] + 9)
  print(dp[1][len(S) - 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"}]