[백준] 10872번 : 팩토리얼 - Python(파이썬)

https://www.acmicpc.net/problem/10872

a=input()
a=int(a)
num=1
if a==0 :
    print(1)
else :
    for i in range(1,a+1) :
        num=num*i
    print(num)