#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(n);++i)
#define all(a) (a).begin(),(a).end()
#define dunk(a) cout << (a) << endl
using namespace std;
typedef long long ll;

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	int Aw, Ab, Bw, Bb, c, d;
	cin >> Aw >> Ab >> Bw >> Bb >> c >> d;
	if (Ab <= c) {
		Aw -= c - Ab;
		Bw += c - Ab;
	}
	if (Bw <= d) {
		Aw += Bw;
	}
	else {
		Aw += d;
	}

	dunk(Aw);
	return 0;
}