Problem C: n!

Memory Limit:128 MB Time Limit:1.000 S
Judge Style:Text Compare Creator:
Submit:64 Solved:23

Description

输入一个整数n(1<n<1000),输出n!的精确值,n!=1*2*3*4*...*n。

Input

一个整数n

Output

n的阶乘值

Sample Input Copy

3

Sample Output Copy

6