1433: 用函数求1+2+3+...+n的和

Memory Limit:128 MB Time Limit:1.000 S
Judge Style:Text Compare Creator:
Submit:19 Solved:14

Description

请用函数求出1+2+3+4+···+n的值

Input

整数n

Output

算式的值

Sample Input Copy

5

Sample Output Copy

15