#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <cmath>
#include <string>
#include <vector>
#include <algorithm>
#include <queue>
#include <map>
#include <functional>
#include <set>
#include <numeric>
#include <stack>
#include <utility>
//#include "util.h"

using namespace std;
typedef long long lint;
typedef pair<lint, lint> Pii;

#define PI 3.14159265358979323846
#define EPS 1e-6
#define MOD ((lint)1000000007)
#define MIN(a,b) ((a)<(b)?(a):(b))
#define MAX(a,b) ((a)>(b)?(a):(b))

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

	if (Ab >= C)
		cout << Aw + MIN(Bw, D) << endl;
	else
		cout << Aw - (C - Ab) + MIN(Bw + (C - Ab), D) << endl;

	return 0;
}