import java.util.*;
import java.lang.*;
import java.io.*;

class Ideone{
    public static void main(String[] args) throws Exception{
        // your code goes here
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String[] lines = br.readLine().split(" ");
        int aw = Integer.parseInt(lines[0]);
        int ab = Integer.parseInt(lines[1]);

        lines = br.readLine().split(" ");
        int bw = Integer.parseInt(lines[0]);
        int bb = Integer.parseInt(lines[1]);

        lines = br.readLine().split(" ");
        int c = Integer.parseInt(lines[0]);
        int d = Integer.parseInt(lines[1]);

        c -= ab;
        if(c>0){
            aw-=c;
            bw+=c;
        }
        
        System.out.println(aw+Math.min(bw,d));
    }
}