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

class Main {
	
	public static void out (Object o) {
		System.out.println(o);
	}
		
	public static void main (String[] args) throws IOException {
		BufferedReader br = 
			new BufferedReader(new InputStreamReader(System.in));
		
		String[] line1 = br.readLine().split(" ");
		String[] line2 = br.readLine().split(" ");
		String[] line3 = br.readLine().split(" ");
		
		int aw = Integer.parseInt(line1[0]);
		int ab = Integer.parseInt(line1[1]);
		int bw = Integer.parseInt(line2[0]);
		int bb = Integer.parseInt(line2[1]);
		int c  = Integer.parseInt(line3[0]);
		int d  = Integer.parseInt(line3[1]);
		
		if (c > ab) {
			c -= ab;
			aw -= c;
			bw += c;
		}
		
		out(aw + Math.min(d , bw));
	}
}