
'''simple docstring'''







def 				_snake_case (		lowercase			,    lowercase						)       ->       Tuple:
				sequence.append(lowercase						)

				__a       :     Optional[Any]								=	0
				while sequence[index] != target:
								index += 1

				sequence.pop()

				if index == len(lowercase						):
								return None

				return index


if __name__ == "__main__":
					__SCREAMING_SNAKE_CASE		:  str        =      input('Enter numbers separated by comma:\n').strip()
					__SCREAMING_SNAKE_CASE		:  List[str]        =      [int(item) for item in user_input.split(',')]

					__SCREAMING_SNAKE_CASE		:  Optional[int]        =      input('Enter a single number to be found in the list:\n')
					__SCREAMING_SNAKE_CASE		:  Dict        =      int(target_input)
					__SCREAMING_SNAKE_CASE		:  Optional[Any]        =      sentinel_linear_search(sequence, target)
					if result is not None:
										print(f'''{target} found at positions: {result}''')
					else:
										print('Not found')

'''simple docstring'''







def 				_snake_case (		lowercase						)       ->       int:
				if not isinstance(lowercase			,    lowercase						):
								__a       :     Union[str, Any]								=	F"""Input value of [number={number}] must be an integer"""
								raise TypeError(lowercase						)
				if number < 1:
								raise ValueError("""Input must be a positive integer"""						)
				return number * (2 * number - 1)


if __name__ == "__main__":
					import doctest

					doctest.testmod()