CF1062D.Fun with Integers

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 $1 \lt |x|$ 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?

给你一个大于等于 $2$ 的正整数 $n$。对于任意一对整数 $a$ 和 $b$（满足 $2 \le |a|, |b| \le n$），当且仅当存在一个整数 $x$ 满足 $1 \lt |x|$，且 $a \cdot x = b$ 或 $b \cdot x = a$ 时，你才可以将 $a$ 变换为 $b$；其中 $|x|$ 表示 $x$ 的绝对值。

每次完成这样的变换后，你的得分增加 $|x|$ 分，并且此后不允许再将 $a$ 变换为 $b$，也不允许将 $b$ 变换为 $a$。

初始得分为 $0$。你可以从任意一个整数开始，并可进行任意多次变换。你能获得的最高得分是多少？

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

一行包含一个整数 $n$（$2 \le n \le 100\,000$）——即上述给定的整数。

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 $0$.

输出一个整数——通过变换所能达到的最高得分。如果对于所有可能的起始整数，都无法执行哪怕一次变换，则输出 $0$。

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.

在第一个例子中，变换过程为 $2 \rightarrow 4 \rightarrow (-2) \rightarrow (-4) \rightarrow 2$。

在第三个例子中，甚至无法执行一次变换。