new_contents: #!/bin/python3
  
  import sys
  
  time = input().strip()
  
  # 12AM = 00:00
  # 12PM = 12:00
  # 01PM = 13:00
  
  meridian = time[-2:]
  time = time[:-2]
  hour, minute, second = time.split(":")
  hour = int(hour, 10)
  
  if meridian == "PM":
      if hour != 12:
          hour += 12
  else:
      if hour == 12:
          hour = 0
  
  print("{:0>2d}:{}:{}".format(hour, minute, second))
  
subject: Create time_conversion.py