#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  int s;
  cin >> n;
  s = n;
  int k = 2;
  while (k <= n) {
    if (n % k == 0) {
      s += n / k;
      n = n / k;
    } else
      k++;
  }
  cout << s;
  return 0;
}
