Bedtime Reading I

Time limit2sMemory limit512 MB

Summary

Given an integer I, compute the sum of all its divisors.

Level: Easy2 of 10
Topics: Math, Number theory, Brute force
Solved: No attempts yet

Problem

The sigma function of a number is the sum of that number's divisors. For example, the divisors of 12 are 1, 2, 3, 4, 6, and 12, so the sigma function of 12 is 28.

Given an integer $I$ , compute the sigma function of $I$ .

Input

The first line contains an integer $I$ ( $1 \le I \le 1\,000\,000$ ).

Output

Print the sum of all divisors of $I$ on the first line.

Examples3

Example 1
Input
```
12
```
Expected output
```
28
```
Example 2
Input
```
1
```
Expected output
```
1
```
Example 3
Input
```
2
```
Expected output
```
3
```