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

namespace yukicoder
{
    public class Program
    {
        public static void Main()
        {
            var a = Console.ReadLine().Split(' ').Select(x => int.Parse(x)).ToArray();
            var b = Console.ReadLine().Split(' ').Select(x => int.Parse(x)).ToArray();
            if (a[0] == a[1]&& b[0] == b[1])
            {
                Console.WriteLine(a[0] + 1);
            }
            else
            {
                Console.WriteLine(Math.Max(a[0], a[1]));
            }
        }
    }
}