#include <bits/stdc++.h>   using namespace std;   int n;   int main() {     ios_base::sync_with_stdio(0);     cin.tie(0);     cin >> n;     long long ans = 0;     for (int i = 2; i <= n; i++)       for (int j = i + i; j <= n; j += i) ans += j / i;     cout << ans * 4 << endl;   }   