#include <bits/stdc++.h>
using namespace std;

int main()
{
int i;
int Aw;
int Ab;
int Bw;
int Bb;
int C;
int D;

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

	i = C - Ab;
	if( i > 0 )
	{
		Aw	-= i;
		Bw	+= i;
	}

	if( D > Bw )
		Aw	+= Bw;
	else
		Aw	+= D;

	cout << Aw << endl;

	return 0;
}