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

class Program
{
    static string InputPattern = "Input5";

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

        if (InputPattern == "Input1") {
            WillReturn.Add("2 1");
            WillReturn.Add("1 2");
            WillReturn.Add("2 3");
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("2 0");
            WillReturn.Add("0 3");
            WillReturn.Add("2 1");
        }
        else if (InputPattern == "Input3") {
            WillReturn.Add("3 0");
            WillReturn.Add("2 3");
            WillReturn.Add("0 5");
        }
        else if (InputPattern == "Input4") {
            WillReturn.Add("43682 82641");
            WillReturn.Add("54647 3647");
            WillReturn.Add("92674 64591");
        }
        else {
            string wkStr;
            while ((wkStr = Console.ReadLine()) != null) WillReturn.Add(wkStr);
        }
        return WillReturn;
    }

    static void Main()
    {
        List<string> InputList = GetInputList();
        int[] wkArr = { };
        Action<int> SplitAct = (pIndY) =>
            wkArr = InputList[pIndY].Split(' ').Select(X => int.Parse(X)).ToArray();

        int ACntWhite, ACntBlack;
        int BCntWhite, BCntBlack;
        int TakeCntFromA, TakeCntFromB;

        SplitAct(0); ACntWhite = wkArr[0]; ACntBlack = wkArr[1];
        SplitAct(1); BCntWhite = wkArr[0]; BCntBlack = wkArr[1];
        SplitAct(2); TakeCntFromA = wkArr[0]; TakeCntFromB = wkArr[1];

        Action DebugPrintAct = () =>
        {
            //Console.WriteLine(new string('■', 20));
            //Console.WriteLine("袋Aの白={0}、黒={1}。袋Bの白={2}、黒={3}",
            //    ACntWhite, ACntBlack, BCntWhite, BCntBlack);
        };

        DebugPrintAct();

        //Aの袋からBの袋への移動
        if (TakeCntFromA <= ACntBlack) {
            ACntBlack -= TakeCntFromA;
            BCntBlack += TakeCntFromA;
        }
        else {
            int FirstMoveCnt = ACntBlack;
            ACntBlack = 0;
            BCntBlack += FirstMoveCnt;
            int SecondMoveCnt = TakeCntFromA - FirstMoveCnt;
            ACntWhite -= SecondMoveCnt;
            BCntWhite += SecondMoveCnt;
        }

        DebugPrintAct();

        //Bの袋からAの袋への移動
        if (TakeCntFromB <= BCntWhite) {
            BCntWhite -= TakeCntFromB;
            ACntWhite += TakeCntFromB;
        }
        else {
            int FirstMoveCnt = BCntWhite;
            BCntWhite = 0;
            ACntWhite += FirstMoveCnt;
            int SecondMoveCnt = TakeCntFromB - FirstMoveCnt;
            BCntBlack -= SecondMoveCnt;
            ACntBlack += SecondMoveCnt;
        }

        DebugPrintAct();

        Console.WriteLine(ACntWhite);
    }
}