#include <bits/stdc++.h>
using namespace std;
int output(int n) {
  int sum = 0;
  while (n != 1) {
    int i;
    for (i = 2; i * i <= n; i++)
      if (n % i == 0) {
        sum += n;
        n /= i;
        break;
      }
    if (i * i > n) {
      sum += n;
      break;
    }
  }
  return ++sum;
}
int main() {
  int t;
  t = 1;
  while (t--) {
    int n;
    cin >> n;
    cout << output(n) << endl;
  }
  return 0;
}
