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

1028306548 224346172 2054738392 8539207488 94344524 4816051228 5867563092 1962150044 641839188 332342852 6587875268 4721174212 12600 115440 4586497300 10630118936 40580456 1286328 6225539588 6275533596 92 8 434692 52 1762017168 33141852 440 3652070664 11101694484 1065137992 12898363344 10983871880 1856988304 64 8885348 28 0
#include <bits/stdc++.h>
const long long MXN = 1e5 + 12;
const double eps = 1e-10;
const double pi = acos(-1.0);
const long long OO = 1e18 + 1;
const int MNN = 1e5 + 1;
const int MOD = 1e9 + 7;
using namespace std;
int n;
long long sum;
bool used[MXN];
long long bfs(int x) {
  long long ans = 0;
  queue<int> q;
  q.push(x);
  used[2] = 1;
  while (!q.empty()) {
    int x = q.front();
    q.pop();
    for (int i = 2; i <= n / x; i++) {
      if (used[i * x] == 0) {
        ans += i * 4;
        q.push(x * i);
        used[x * i] = 1;
      }
    }
    for (int i = 2; i <= sqrt(x); i++) {
      if (x % i == 0) {
        if (used[x / i] == 0) {
          ans += i * 4;
          q.push(x / i);
          used[x / i] = 1;
        }
        if (used[i] == 0) {
          ans += x / i * 4;
          q.push(i);
          used[i] = 1;
        }
      }
    }
  }
  return ans;
}
int main() {
  ios_base::sync_with_stdio(0), cout.tie(0), cin.tie(0);
  ;
  cin >> n;
  for (int i = 2; i <= n; i++) {
    if (used[i] == 0) {
      sum += bfs(i);
    }
  }
  cout << sum;
  return 0;
}
