import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Scanner;

import static java.lang.System.in;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(in));
        String[] inputs = reader.readLine().split(" ");
        int aw = Integer.parseInt(inputs[0]);
        int ab = Integer.parseInt(inputs[1]);
        inputs = reader.readLine().split(" ");
        int bw = Integer.parseInt(inputs[0]);
        int bb = Integer.parseInt(inputs[1]);
        inputs = reader.readLine().split(" ");
        int c = Integer.parseInt(inputs[0]);
        int d = Integer.parseInt(inputs[1]);


        if (ab < c) {
            aw = aw - (c - ab);
            bw = bw + (c-ab);
        }

        if (bw < d) {
            aw = aw + bw;
        } else {
            aw = aw + d;
        }

        System.out.println(aw);


    }
}