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;
inline long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; }
inline long long lcm(long long a, long long b) { return a / gcd(a, b) * b; }
int month[15] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
int dir[8][2] = {{-1, 0},  {1, 0}, {0, -1}, {0, 1},
                 {-1, -1}, {1, 1}, {1, -1}, {-1, 1}};
const int MAXN = 1e5 + 5;
const int INF = 1 << 30;
const long long mod = 1e9 + 7;
const double eps = 1e-8;
const long long inff = 0x3f3f3f3f3f3f3f3f;
long long n, p, m, k, cnt, a[25], ans = 0;
bool vis[MAXN];
int main() {
  cin >> n;
  m = sqrt(n) + 1;
  for (int i = 2; i <= m; i++) {
    if (n % i == 0) {
      k = n / i - 1;
      ans += i * 4 * k;
    }
  }
  cout << ans << endl;
}
