import java.util.Arrays;
import java.util.LinkedList;
import java.util.Scanner;

public class Main {
	
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		
		final int Aw = sc.nextInt();
		final int Ab = sc.nextInt();
		final int Bw = sc.nextInt();
		final int Bb = sc.nextInt();
		
		final int C = sc.nextInt();
		final int D = sc.nextInt();
		
		System.out.println(Aw + Math.min(D - Math.max(0, C - Ab), Bw));
		
	}
	
}