

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.')






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.')



