using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;
using System.Globalization;

class Program
{
    static int NN => int.Parse(ReadLine());
    static long[] NList => ReadLine().Split().Select(long.Parse).ToArray();
    static long[][] NArr(long n) => Enumerable.Repeat(0, (int)n).Select(_ => NList).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var c = NList;
        if (c[0] * 2 == c[1] || c[0] == c[1]) WriteLine(4);
        else if (c[0] * 2 > c[1] && c[0] < c[1]) WriteLine(8);
        else WriteLine(0);
    }
}