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

class Program
{
    static void Main(string[] args)
    {
        var input = Console.ReadLine().Split().Select(int.Parse).ToArray();
        var X = input[0];
        var Y = input[1];
        Console.WriteLine(Math.Abs(Math.Max(X, Y) - Math.Min(X, Y) * 3));
    }
}