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;
template <class T>
bool cmin(T &a_, T b_) {
  return a_ > b_ ? (a_ = b_, true) : false;
}
template <class T>
bool cmax(T &a_, T b_) {
  return a_ < b_ ? (a_ = b_, true) : false;
}
template <class T>
void OUT(T s_) {
  cout << s_ << '\n';
  exit(0);
}
const int maxn = 1.001e5;
unsigned long long dp[maxn];
void process() {
  for (int i = (int)(2); i <= (int)(maxn - 1); ++i) {
    for (int j = i + i; j < maxn; j += i) {
      dp[j] += dp[j - i] + (unsigned long long)j / i;
    }
  }
}
void Fan_chipu() {
  process();
  int n;
  cin >> n;
  unsigned long long ans = 0;
  for (int i = (int)(1); i <= (int)(n); ++i) cmax(ans, dp[i]);
  cout << ans * 4;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.precision(10);
  cout << fixed;
  Fan_chipu();
}
