#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  scanf("%d", &n);
  long long ans = n;
  for (int i = 2; i * i <= n; i++) {
    while (n % i == 0) {
      n /= i;
      ans += n;
    }
  }
  if (n != 1) {
    ans++;
  }
  cout << ans;
  return 0;
}
