using System;
using System.Text;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
using System.Runtime.Serialization.Formatters;
using static System.Console;
using static System.Math;

namespace YukiCoder
{
    public class Program
    {
        public static void Main(string[] args)
        {
            new Program().Solve();
        }

        public void Solve()
        {
            int n = int.Parse(ReadLine());

            int sum = 0;
            for (int i = 1; i <= n; i++)
            {
                if (n % i == 0)
                {
                    sum += i;
                }
            }
            
            WriteLine(sum);
        }
        
    }
}