D. Fun with Integerstime limit per test2 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard outputYou 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?InputA single line contains a single integer n (2 \le n \le 100\,000) — the given integer described above.OutputPrint 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.ExamplesInput4Output8Input6Output28Input2Output0NoteIn 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.
Input4
Output8
['dfs and similar', 'graphs', 'implementation', 'math', '*1800']