#include <iostream>
#include <string>
#include <vector>
using namespace std;

int main(){
	int Aw,Ab,Bw,Bb,C,D;
	cin >> Aw >> Ab >> Bw >> Bb >> C >> D;
	if(C<=Aw){
		Bw+=C;
		Aw-=C;
	}
	else{
		Bw+=Aw;
		Aw=0;
	}
	Aw+= (D<=Bw)? D:Bw;
	cout << Aw << endl;
	return 0;
}