package com.company;

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        Long value = scanner.nextLong();
        if(value % 2 == 0)
        {
            value /=2;
        }
        Long sum = 0L;
        for(Long i = 1L; i * i <= value;i++)
        {
            if(value % i == 0)
            {
                Long other = value / i;
                sum += i;
                if(i < other)
                {
                    sum += other;
                }
            }
        }

        System.out.println(sum.toString());
    }
}