import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner koko = new Scanner(System.in);
       int aw = koko.nextInt();
       int ab = koko.nextInt();
       int bw = koko.nextInt();
       int bb = koko.nextInt();
       int c = koko.nextInt();
       int d = koko.nextInt();
       int minus, plus;
       if(ab>c){
           minus = 0;
       }else{
           minus = c-ab;
       }
       if((bw+minus)>=d){
           plus = d;
       }else{
           plus = bw + minus;
       }
       System.out.println(aw-minus+plus);
    }
}