#include <bits/stdc++.h>

using namespace std;

int main()
{
    int aw, ab, bw, bb; cin >> aw >> ab >> bw >> bb;
    int c, d; cin >> c >> d;

    c -= min(c, ab);
    aw -= c;
    bw += c;

    cout << aw + min(bw, d) << endl;
}