Fun with Integers

题意翻译

给定一个大于或等于$2$的正整数$n$。对于每对整数$a$和$b$，$(2≤|a|,|b|≤n)$，当且仅当存在整数x，满足$1<|x|$且$(a\cdot x=b$或$b\cdot x=a)$，才能将$a$转换为$b$，其中$|x|$表示$x$的绝对值。 在这样的转换之后，你的分数增加了$|x|$，并且你就不允许将再将$a$转换为$b$或$b$再转换为a了。 最初，您的得分为$0$.您可以从任何整数开始，并可以根据需要将其多次转换。求可以达到的最高分是多少？

题目描述

You are given a positive integer $ n $ greater or equal to $ 2 $ . For every pair of integers $ a $ and $ b $ ( $ 2 \le |a|, |b| \le n $ ), you can transform $ a $ into $ b $ if and only if there exists an integer $ x $ such that $ 1 < |x| $ and ( $ a \cdot x = b $ or $ b \cdot x = a $ ), where $ |x| $ denotes the absolute value of $ x $ . After such a transformation, your score increases by $ |x| $ points and you are not allowed to transform $ a $ into $ b $ nor $ b $ into $ a $ anymore. Initially, you have a score of $ 0 $ . You can start at any integer and transform it as many times as you like. What is the maximum score you can achieve?

输入输出格式

输入格式

A single line contains a single integer $ n $ ( $ 2 \le n \le 100\,000 $ ) — the given integer described above.

输出格式

Print an only integer — the maximum score that can be achieved with the transformations. If it is not possible to perform even a single transformation for all possible starting integers, print $ 0 $ .

输入输出样例

输入样例 #1

4

输出样例 #1

8

输入样例 #2

6

输出样例 #2

28

输入样例 #3

2

输出样例 #3

0

说明

In the first example, the transformations are $ 2 \rightarrow 4 \rightarrow (-2) \rightarrow (-4) \rightarrow 2 $ . In the third example, it is impossible to perform even a single transformation.