


'''simple docstring'''

def _SCREAMING_SNAKE_CASE (A    ,					A			)			->			str:






       """simple docstring"""







       lowercase__      =					''''''
       for word_or_phrase in separated:
              if not isinstance(A    ,					A			):
                     raise Exception('''join() accepts only strings to be joined'''			)
              joined += word_or_phrase + separator
       return joined.strip(A			)


if __name__ == "__main__":
 from doctest import testmod

 testmod()








'''simple docstring'''

def _SCREAMING_SNAKE_CASE (A = 1_000			)			->			int:






       """simple docstring"""







       return sum(2 * a * ((a - 1) // 2) for a in range(3    ,					n + 1			)			)


if __name__ == "__main__":
 print(solution())




