Given an integer ~n~, return the sum of all of its unique factors.

Input

Your first line will contain an integer ~n~.

Output

The sum of all unique factors of ~n~.

Constraints

For all test cases:

• ~1 \le n \le 10^7~

Example 1

Input

10

Output

18

Explanation

The factors of ~10~ are ~1, 2, 5, 10~. The sum of these factors is ~18~.

Example 2

Input

4

Output

7

Explanation

The factors of ~4~ are ~1, 2, 4~. The sum of these factors is ~7~.

Python Template

n = int(input())