#include <iostream>
using namespace std;

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

    if(c > ab){
        mv = c - ab;
        aw -= mv;
        (d < bw + mv) ? aw += d : aw += bw + mv; 
    }else
        (d < bw) ? aw += d : aw += bw; 

    cout << aw << endl;

    return 0;
}