#include <iostream> 
#include <algorithm> 
using namespace std;

int main() {
    int Aw, Ab, Bw, Bb, C, D;
    cin >> Aw >> Ab >> Bw >> Bb >> C >> D;
    cout << Aw - max(0, C - Ab) + min(D, Bw + max(0, C - Ab)) << endl;
}