#include <iostream>
using namespace std;

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