//yukicoder 149 "碁石の移動"
//http://yukicoder.me/problems/295
#include <bits/stdc++.h>
using namespace std;



int main() {
	int c, d, aw, ab, bw, bb;
	cin >> aw >> ab;
	cin >> bw >> bb;
	cin >> c >> d;
	if ( ab >= c) {
		if (bw >= d) cout << aw + d;
		else cout << aw + bw;
	} else {
		if (bw + c - ab >= d) cout << aw + bw + d - c;
		else cout << aw + bw;
	}
	cout << endl;
	return 0;
}