#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <iomanip>
#include <stack>
#include <algorithm>
#include <string>
#include <map>
#include <iterator>
#include <set>
#include <queue>
#include <bitset>
#include <cassert>

using namespace std;

int main() {

    int Aw, Ab;
    cin >> Aw >> Ab;
    int Bw, Bb;
    cin >> Bw >> Bb;
    int C, D;
    cin >> C >> D;

    if (C > Ab) {
        Aw -= (C - Ab);
        Bw += (C - Ab);
    }

    cout << Aw + min(Bw,D) << endl;


    return 0;

}