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;
long long int mul(long long int x, long long int y) {
  long long int ans = 1;
  while (y > 0) {
    if (y & 1) ans = (ans * x) % 1000000007;
    y /= 2;
    x = (x * x) % 1000000007;
  }
  return ans;
};
long long int p[100005], a[100005], ans[100005];
long long int prnt(long long int x) {
  if (p[x] == x)
    return x;
  else
    return p[x] = prnt(p[x]);
};
int main() {
  long long int n, i, j, aa, bb;
  cin >> n;
  for (i = 2; i <= n; i++) p[i] = i;
  for (i = 2; i <= n; i++) {
    for (j = i * 2; j <= n; j += i) {
      a[i] += (j / i);
      aa = prnt(i);
      bb = prnt(j);
      p[bb] = aa;
    }
  }
  long long int fin = 0;
  for (i = 2; i <= n; i++) {
    aa = prnt(i);
    ans[aa] += a[i];
  }
  for (i = 2; i <= n; i++) fin = max(fin, ans[i]);
  cout << 4 * fin << "\n";
  return 0;
}
