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

class Solution
{
    static void Main()
    {
        var c = Console.ReadLine().Split(' ');
        var result = "";
        var one = c.Select(a => (a != "?") ? int.Parse(a) : 1).ToArray();
        if (one.Max() == one[1] || one.Min() == one[1])
        {
            result += "1";
        }

        var four = c.Select(a => (a != "?") ? int.Parse(a) : 4).ToArray();
        if (four.Max() == four[1] || four.Min() == four[1])
        {
            result += "4";
        }

        Console.WriteLine(result);
    }
}