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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#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  scanf("%i", &n);
  vector<set<int>> v(n + 5);
  list<int> vis;
  long long c = 0;
  vis.push_back(2);
  for (int i = 2; i <= n; i++) {
    int j = 2;
    while (i * j <= n) {
      v[i].insert(i * j);
      v[i * j].insert(i);
      j++;
    }
  }
  for (list<int>::iterator it = vis.begin(); it != vis.end(); it++) {
    int a = *it;
    for (set<int>::iterator jt = v[a].begin(); jt != v[a].end(); jt++) {
      int b = *jt;
      vis.push_back(b);
      if (v[b].find(a) != v[b].end()) v[b].erase(v[b].find(a));
      if (a > b)
        c += 4 * (long long)(a / b);
      else
        c += 4 * (long long)(b / a);
    }
  }
  printf("%lli\n", c);
  return 0;
}
