using System;

public class Hello
{
    public static long a, b, n, m;
    static void Main()
    {
        string[] line = Console.ReadLine().Trim().Split(' ');
        a = long.Parse(line[0]);
        b = long.Parse(line[1]);
        n = long.Parse(line[2]);
        m = long.Parse(line[3]);
        getAns();
    }
    static void getAns()
    {
        if (a == b) { Console.WriteLine(a); return; }
        long ans;
        if (a > b) ans = b + (a - b) / (n + 1);
        else ans = a + (b - a) / (m + 1);
        Console.WriteLine(ans);
    }
}