Problem B: 求n!

Problem B: 求n!

Time Limit: 1 Sec  Memory Limit: 128 MB
Submit: 2  Solved: 2
[Submit] [Status] [Web Board] [Creator:]

Description

n! = 1 * 2 * …… * n 
用递归的方法求n!


Input

n (n<=50)

Output

n!

Sample Input Copy

4

Sample Output Copy

24

HINT

递归