'''
n! = n * (n - 1) * (n - 2) * (n - 3) * ... * 1
n! = n * (n - 1)!
5! = 5 * 4 * 3 * 2 * 1
5! = 5 * 4!
5! = 120
0! = 1
'''

def factorial_recursive(n):
    if n <= 1:
        return 1
    return n * factorial_recursive(n - 1)

#factorial_recursive(5)
#return 5 * factorial_recursive(4)
#           return 4 * factorial_recursive(3)
#                      return 3 * factorial_recursive(2)
#                                 return 2 * factorial_recursive(1)
#                                            return 1
