#include <iostream>
#include <algorithm>
using namespace std;
int main(){
  int aw,ab;
  int bw,bb;
  int c,d;
  cin >> aw >> ab >> bw >> bb >> c >> d;
  cout << aw - max(0,c-ab) + min(d,bw+max(0,c-ab)) << endl;
  return 0;
}