2089: 挑战求和3

Memory Limit:128 MB Time Limit:1.000 S
Judge Style:Text Compare Creator:
Submit:86 Solved:71

Description

输入一个正整数n,求
1!+2!+3!+……+N!的结果.

Input

一个正整数n

Output

结果

Sample Input Copy

3

Sample Output Copy

9

HINT

9=1+(1*2)+(1*2*3)

Source/Category