





def   _A (	SCREAMING_SNAKE_CASE  :     int = 998_001		):





  """simple docstring"""



  a__			:      Optional[Any]            =0
  for i in range(999 , 99 , -1		):  # 3 digit numbers range from 999 down to 100
    for j in range(999 , 99 , -1		):
      a__			:      int            =str(i * j		)
      if product_string == product_string[::-1] and i * j < n:
        a__			:      Optional[Any]            =max(SCREAMING_SNAKE_CASE , i * j		)
  return answer


if __name__ == "__main__":
     print(F"""{solution() = }""")












def   _A (	SCREAMING_SNAKE_CASE  :     int		):





  """simple docstring"""



  barcode //= 10  # exclude the last digit
  a__			:      int            =False
  a__			:      List[str]            =0

  # extract and check each digit
  while barcode != 0:
    a__			:      Optional[Any]            =1 if checker else 3
    s += mult * (barcode % 10)
    barcode //= 10
    a__			:      Union[str, Any]            =not checker

  return (10 - (s % 10)) % 10
def   _A (	SCREAMING_SNAKE_CASE  :     int		):





  """simple docstring"""



  return len(str(SCREAMING_SNAKE_CASE		)		) == 13 and get_check_digit(SCREAMING_SNAKE_CASE		) == barcode % 10
def   _A (	SCREAMING_SNAKE_CASE  :     str		):





  """simple docstring"""



  if str(SCREAMING_SNAKE_CASE		).isalpha():
    a__			:      Tuple            =f'''Barcode \'{barcode}\' has alphabetic characters.'''
    raise ValueError(SCREAMING_SNAKE_CASE		)
  elif int(SCREAMING_SNAKE_CASE		) < 0:
    raise ValueError("The entered barcode has a negative value. Try again."		)
  else:
    return int(SCREAMING_SNAKE_CASE		)


if __name__ == "__main__":
     import doctest

     doctest.testmod()
     UpperCAmelCase			:			List[str]	  = get_barcode(input("""Barcode: """).strip())

     if is_valid(barcode):
          print(F"""'{barcode}' is a valid barcode.""")
     else:
          print(F"""'{barcode}' is NOT a valid barcode.""")






