28237
 13190
 39914
 81367
 8554
 61106
 67448
 39004
 22308
 16054
 71468
 60501
 100
 300
 59632
 90783
 5611
 1000
 69475
 69753
 10
 5
 582
 8
 36961
 5071
 20
 53213
 92775
 28738
 100000
 92280
 37944
 9
 2627
 7
 3

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#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <vector>
#include <iterator>
#include <string>
#include <algorithm>
#include <utility>
#include <string.h>
#include <math.h>
#include <map>
#include <iostream>
#include <set>

using namespace std;

vector<__int64> a;
vector<__int64> l;

int main()
{
	freopen("input.txt", "r", stdin);
	freopen("output.txt", "w", stdout);

	int n;
	__int64 s = 0;
	cin >> n;

	for (int i = 2; i <= n / 2; i++)
	{
		__int64 k = n / i;
		s += (k * (k + 1)) / 2 - 1;
	}

	s *= 4;
	cout << s;

	return 0;
}