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

class Program
{
    static string InputPattern = "Input3";

    static List<string> GetInputList()
    {
        var WillReturn = new List<string>();

        if (InputPattern == "Input1") {
            WillReturn.Add("1 1");
            WillReturn.Add("1 0");
            //1
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("10 1");
            WillReturn.Add("1 0");
            //10
        }
        else {
            string wkStr;
            while ((wkStr = Console.ReadLine()) != null) WillReturn.Add(wkStr);
        }
        return WillReturn;
    }

    static void Main()
    {
        List<string> InputList = GetInputList();
        int[] wkArr = { };

        Action<string> SplitAct = (pStr) =>
            wkArr = pStr.Split(' ').Select(X => int.Parse(X)).ToArray();

        SplitAct(InputList[0]);
        int GoalX = wkArr[0], GoalY = wkArr[1];

        SplitAct(InputList[1]);
        int HuX = wkArr[0], HuY = wkArr[1];

        int Tesuu = Math.Max(GoalX, GoalY);

        //迂回が必要かを判定
        if (GoalX == GoalY && HuX == HuY)
            Tesuu++;

        Console.WriteLine(Tesuu);
    }
}