#include <iostream>
using namespace std;
void f(int n) {
  int s = 1, d, j, nr = 0;
  for (d = 3; d <= n; d++) {
    if (d % 2 == 0 && n % d == 0)
      s = s + d;
    else if (n % d == 0 && d % 2 == 1) {
      for (j = 3; j * j <= d; j = j + 2)
        if (d % j == 0)
          nr++;
      if (nr != 0)
        s = s + d;
    }
    nr = 0;
  }
  cout << s;
}
int main() {
    int x;cin>>x;
  f(x);
  return 0;
}