n = int(input())
even_or_odd = n%2
factorial2 = 1
for x in range(1, 1 + n//2):
factorial2 *= 2*x + even_or_odd
print(factorial2)
biA9IGludChpbnB1dCgpKQpldmVuX29yX29kZCA9IG4lMgpmYWN0b3JpYWwyID0gMQpmb3IgeCBpbiByYW5nZSgxLCAxICsgbi8vMik6CglmYWN0b3JpYWwyICo9IDIqeCArIGV2ZW5fb3Jfb2RkCnByaW50KGZhY3RvcmlhbDIp