using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            long N = long.Parse(Console.ReadLine());
            long i = 1;
            long answer = 0;
            while(i <= N)
            {
                if(N % i == 0)
                {
                    answer += N / i;
                }
                i++;
            }
            Console.WriteLine(answer);
        }
    }
}