
# n! = 1 * 2 * 3 * ... (n-2) * (n-1) * n
def factorial_1(n):
	변수 = 1
	for i in range(1, n + 1):
		변수 *= i

	return 변수

# 0! = 1
# n! = n * (n-1)!
def factorial_2(n):
	if n == 0:
		return 1
	else:
		return n * factorial_2(n-1)

print(factorial_1(5))
print(factorial_2(5))