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 n;
map<long long, map<long long, long long> > us;
long long ans = 0;
bool rec(long long v, long long sm = 0) {
  if (abs(v) < 2) return 0;
  if (sm == 140) {
    cout << v << ' ';
    return 1;
  }
  for (long long i = -n; i <= n; i++) {
    if (abs(i) > 1 && i != v && !us[v][i] &&
        (!(abs(v) % abs(i)) || !(abs(i) % abs(v)))) {
      us[v][i] = us[i][v] = 1;
      long long sm1;
      if (!(abs(v) % abs(i)))
        sm1 = abs(abs(v) / abs(i));
      else
        sm1 = abs(abs(i) / abs(v));
      if (sm1 == 1) continue;
      if (rec(i, sm + sm1)) {
        cout << v << ' ';
        return 1;
      }
      us[v][i] = us[i][v] = 0;
    }
  }
  ans = max(ans, sm);
  return 0;
}
long long a[400000];
long long del(long long v) {
  long long res = 0;
  for (long long i = 2; i * i <= v; i++)
    if (!(v % i)) {
      res += i;
      if (v / i != i) res += v / i;
    }
  return res;
}
signed main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n;
  a[4] = a[5] = 8;
  a[6] = a[7] = 28;
  for (long long i = 8; i <= n; i++) {
    if (i & 1)
      a[i] = a[i - 1];
    else
      a[i] = a[i - 1] + del(i) * 4;
  }
  cout << a[n];
  return 0;
}
