import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        long sum = 1;
        for(int i = 2; i <= Math.sqrt(n); i++) {
            if(n % i == 0) {
                sum += i;
                sum += (n / i);
            }
        }
        System.out.println(sum);
    }
}