#include <iostream>
#include <vector>
#include <cstdio>
#include <sstream>
#include <map>
#include <string>
#include <algorithm>
#include <queue>
#include <cmath>
#include <set>
using namespace std;

int main(){
	int Aw,Ab;
	cin >> Aw >> Ab;
	int Bw,Bb;
	cin >> Bw >> Bb;

	int C,D;
	cin >> C >> D;

	int x = min(Ab, C);
	Bb += x;
	Ab -= x;

	Bw += C-x;
	Aw -= C-x;

	int y = min(Bw, D);
	Aw += y;
	Bw -= y;

	Ab += D-y;
	Bb -= D-y;

	cout << Aw << endl;


	return 0;
}