#include <bits/stdc++.h>

using namespace std;

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

  c = max(0, c - ab);
  aw -= c;
  bw += c;
  aw += min(d, bw);
  
  cout << aw << endl;

  return 0;
}