


'''simple docstring'''

def __snake_case      (   UpperCAmelCase_		:		list      ,       UpperCAmelCase_		:		int      ,       UpperCAmelCase_		:		int = 0      ,       UpperCAmelCase_		:		int = 0	):
 lowerCamelCase_  				=						right or len(UpperCAmelCase_	) - 1
 if left > right:
  return -1
 elif list_data[left] == key:
  return left
 elif list_data[right] == key:
  return right
 else:
  return search(UpperCAmelCase_      ,       UpperCAmelCase_      ,       left + 1      ,       right - 1	)


if __name__ == "__main__":
     import doctest

     doctest.testmod()







'''simple docstring'''

def __snake_case      (   UpperCAmelCase_		:		int = 1000	):
 return sum(2 * a * ((a - 1) // 2) for a in range(3      ,       n + 1	)	)


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



