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

public class Test
{
	static void Main()
        {
            var sum = 0L;
            for (int i = 1; i <= 10000; i++)
            {
                long tmp;
                if ((tmp = GetDivisorSum(i)) > i && GetDivisorSum(tmp) == i)
                {
                    sum += tmp + i;
                }
            }
            Console.WriteLine(sum);
        }

        static long GetDivisorSum(long value)
        {
            var prime = new List<int>();
            var devisor = 2;
            var given = value;
            if (value <= 0)
                return 0;
            if (value == 1)
                return 1;
            while (value != 1)
            {
                if (value % devisor == 0)
                {
                    prime.Add(devisor);
                    value /= devisor;
                }
                else
                    devisor++;
            }
            return prime.GroupBy(x => x)
                .Select(x => ((long)Math.Pow(x.Key, x.Count() + 1) - 1) / (x.Key - 1))
                .Aggregate((x, y) => x * y) - given;
        }
}