#include <iostream>
#include <cmath>

using namespace std;

int main() {
  long long n, sum = 0;
  cin >> n;

  for (long long i = 1; i * i <= n; ++i) {
    if (n % i == 0) {
      sum += i;
      if (i != n / i) {
        sum += n / i;
      }
    }
  }

  cout << sum << endl;
  return 0;
}