

class     _a						:


					'''simple docstring'''






					def __init__( self    ,       A__			):
						A__							:    Any        =		size
						A__							:    Optional[int]        =		[0] * size
						A__							:    Any        =		[0] * size






					@staticmethod
					def   __A			( A__			):
						return index | (index + 1)






					@staticmethod
					def   __A			( A__			):
						return (index & (index + 1)) - 1






					def   __A			( self    ,       A__    ,       A__			):
						A__							:    Dict        =		value
						while index < self.size:
							A__							:    List[str]        =		self.get_prev(A__			) + 1
							if current_left_border == index:
								A__							:    int        =		value
							else:
								A__							:    Optional[int]        =		max(A__    ,       A__    ,       A__			)
							A__							:    List[str]        =		self.get_next(A__			)






					def   __A			( self    ,       A__    ,       A__			):
						right -= 1  # Because of right is exclusive
						A__							:    Optional[Any]        =		0
						while left <= right:
							A__							:    int        =		self.get_prev(A__			)
							if left <= current_left:
								A__							:    Union[str, Any]        =		max(A__    ,       self.tree[right]			)
								A__							:    str        =		current_left
							else:
								A__							:    Any        =		max(A__    ,       self.arr[right]			)
								right -= 1
						return result


if __name__ == "__main__":
	import doctest

	doctest.testmod()






from math import factorial

def 						UpperCamelCase					(lowercase_: int = 20					)     ->      int:
	A__							:    Union[str, Any]        =		2 * n  # middle entry of odd rows starting at row 3 is the solution for n = 1,
	# 2, 3,...
	A__							:    Tuple        =		n // 2

	return int(factorial(lowercase_					) / (factorial(lowercase_					) * factorial(n - k					))					)


if __name__ == "__main__":
	import sys

	if len(sys.argv) == 1:
		print(solution(20))
	else:
		try:
			A_       : List[str]         =			int(sys.argv[1])
			print(solution(n))
		except ValueError:
			print('Invalid entry - please enter a number.')



