using static System.Math;
using System;

public class Hello
{
    public static void Main()
    {
        string[] line = Console.ReadLine().Trim().Split(' ');
        var x = int.Parse(line[0]);
        var y = int.Parse(line[1]);
        line = Console.ReadLine().Trim().Split(' ');
        var x2 = int.Parse(line[0]);
        var y2 = int.Parse(line[1]);
        var ans = getAns(x, y, x2, y2);
        Console.WriteLine(ans);
    }
    public static int getAns(int x, int y, int x2, int y2)
    {
        if (x == y && x2 == y2 && x > x2) return x + 1;
        var xymin = Min(x, y);
        var nx = x - xymin;
        var ny = y - xymin;
        return nx + ny + xymin;
    }
}