using System;
using System.Linq;

namespace ConsoleApplication1
{
    internal class Program
    {
        private static void Main(string[] args)
        {
            var towers = Console.ReadLine().Split(new[] {' '}, StringSplitOptions.RemoveEmptyEntries).Select(int.Parse).ToArray();
            var avg = Math.Round(towers.Average());
            Console.WriteLine(Math.Max(towers.Where(t => t < avg).Select(t => avg - t).Sum(),
                towers.Where(t => t > avg).Select(t => t - avg).Sum()));
        }
    }
}