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;
const long long mod = (long long)1e9 + 7;
long long n, x, ans;
bool col[100002];
queue<long long> qu;
int main() {
  cin >> n;
  if (n == 2 || n == 3) {
    cout << 0 << endl;
    return 0;
  }
  for (long long i = (long long)2; i < (long long)sqrt(n) + 2; i++) {
    if (n % i == 0) break;
    if (i == (long long)sqrt(n) + 1) {
      n--;
      break;
    }
  }
  if (n == 5 || n == 7) n--;
  col[n] = true;
  qu.push(n);
  while (!qu.empty()) {
    x = qu.front();
    qu.pop();
    for (long long i = (long long)2; i < (long long)n; i++) {
      if (col[i] == false) {
        if (x % i == 0 || i % x == 0) {
          col[i] = true;
          qu.push(i);
          ans += i / x + x / i;
        }
      }
    }
  }
  cout << 4 * ans << endl;
  return 0;
}
