#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<ll, ll> P;

#define EACH(i,a) for (auto& i : a)
#define FOR(i,a,b) for (ll i=(a);i<(b);i++)
#define RFOR(i,a,b) for (ll i=(b)-1;i>=(a);i--)
#define REP(i,n) for (ll i=0;i<(n);i++)
#define RREP(i,n) for (ll i=(n)-1;i>=0;i--)
#define debug(x) cout<<#x<<": "<<x<<endl
#define pb push_back
#define ALL(a) (a).begin(),(a).end()

const ll linf = 1e18;
const int inf = 1e9;
const double eps = 1e-12;
const double pi = acos(-1);

template<typename T>
istream& operator>>(istream& is, vector<T>& vec) {
	EACH(x,vec) is >> x;
	return is;
}
template<typename T>
ostream& operator<<(ostream& os, vector<T>& vec) {
	REP(i,vec.size()) {
		if (i) os << " ";
		os << vec[i];
	}
	return os;
}
template<typename T>
ostream& operator<<(ostream& os, vector< vector<T> >& vec) {
	REP(i,vec.size()) {
		if (i) os << endl;
		os << vec[i];
	}
	return os;
}

int main() {
	std::ios::sync_with_stdio(false);
	std::cin.tie(0);
	int Aw, Ab; cin >> Aw >> Ab;
	int Bw, Bb; cin >> Bw >> Bb;
	int C, D; cin >> C >> D;
	{
		int Cb = min(C, Ab);
		int Cw = C - Cb;
		Ab -= Cb;
		Bb += Cb;
		Aw -= Cw;
		Bw += Cw;
	}
	{
		int Dw = min(D, Bw);
		int Db = D - Db;
		Bb -= Db;
		Ab += Db;
		Bw -= Dw;
		Aw += Dw;
	}
	cout << Aw << endl;
}