code: 
  
  
  def   SCREAMING_SNAKE_CASE__						(							snake_case_ = 9_9_8_0_0_1	)			->							int:
  				A__     :							List[Any]   				=0
  				for i in range(9_9_9,	9_9,	-1	):  # 3 digit numbers range from 999 down to 100
  								for j in range(9_9_9,	9_9,	-1	):
  												A__     :							Any   				=str(i * j	)
  												if product_string == product_string[::-1] and i * j < n:
  																A__     :							Optional[int]   				=max(snake_case_,	i * j	)
  				return answer
  
  
  if __name__ == "__main__":
  						print(F"{solution() = }")
  
  
  
  
style_context: 
  
  
  def   SCREAMING_SNAKE_CASE__						(							snake_case_	)			->							int:
  				if number != int(snake_case_	):
  								raise ValueError('''factorial() only accepts integral values'''	)
  				if number < 0:
  								raise ValueError('''factorial() not defined for negative values'''	)
  				A__     :							Union[str, Any]   				=1
  				for i in range(1,	number + 1	):
  								value *= i
  				return value
  
  
  
  def   SCREAMING_SNAKE_CASE__						(							snake_case_	)			->							int:
  				if not isinstance(snake_case_,	snake_case_	):
  								raise ValueError('''factorial() only accepts integral values'''	)
  				if n < 0:
  								raise ValueError('''factorial() not defined for negative values'''	)
  				return 1 if n == 0 or n == 1 else n * factorial(n - 1	)
  
  
  if __name__ == "__main__":
  						import doctest
  
  						doctest.testmod()
  
  						__lowerCamelCase       :       Any				   =			int(input("Enter a positive integer: ").strip() or 0)
  						print(F"factorial{n} is {factorial(n)}")
  
  
  
  