output_description: Print the specified string: `YYMM`, `MMYY`, `AMBIGUOUS` or `NA`.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      S
attempt: a = input()
  i = 0
  n = []
  while i < len(a):
      n.append(a[i])
      i += 1
  pd = n[0] + n[1]
  sd = n[2] + n[3]
  pd = int(pd)
  sd = int(sd)
  if pd > 12:
      if sd >= 1 and sd <= 12:
          print("YYMM")
      elif sd > 12:
          print("NA")
      elif sd < 1:
          print("NA")
  elif pd == 0:
      if sd > 12:
          print("NA")
      if sd > 0 and sd <= 12:
          print("YYMM")
  elif pd <= 12:
      if sd > 12:
          print("MMYY")
      elif sd == 0:
          print("MMYY")
      elif sd <= 12 and sd != 0:
          print("AMBIGUOUS")
  
problem_description: Statement
  
  You have a digit sequence S of length 4. You are wondering which of the
  following formats S is in:
  
    * YYMM format: the last two digits of the year and the two-digit representation of the month (example: `01` for January), concatenated in this order
    * MMYY format: the two-digit representation of the month and the last two digits of the year, concatenated in this order
  
  If S is valid in only YYMM format, print `YYMM`; if S is valid in only MMYY
  format, print `MMYY`; if S is valid in both formats, print `AMBIGUOUS`; if S
  is valid in neither format, print `NA`.
samples: [{"input": "1905", "output": "YYMM\n    \n\nMay XX19 is a valid date, but 19 is not valid as a month. Thus, this string is\nonly valid in YYMM format.\n\n* * *"}, {"input": "0112", "output": "AMBIGUOUS\n    \n\nBoth December XX01 and January XX12 are valid dates. Thus, this string is\nvalid in both formats.\n\n* * *"}, {"input": "1700", "output": "NA\n    \n\nNeither 0 nor 17 is valid as a month. Thus, this string is valid in neither\nformat."}]