using System;
using System.Linq;
using System.Collections.Generic;
using System.IO;

class MyClass
{
    public static void Solve()
    {
        var N = long.Parse(Console.ReadLine());
        long sum = 0;
        for (int i = 1; i * i <= N; i++)
        {
            if (N % i == 0)
            {
                sum += i;
                if (i * i != N)
                {
                    sum += N / i;
                }
            }
        }
        Console.WriteLine(sum);
    }

    public static void Main()
    {
        var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
        Console.SetOut(sw);
        Solve();
        Console.Out.Flush();
    }
}