#coding:utf-8

Aw,Ab=map(int,raw_input().split())
Bw,Bb=map(int,raw_input().split())
C,D=map(int,raw_input().split())

if Ab:
	if 0 <= (Ab-C):
		Bb+=C
		if 0 <= (Bw-D):
			Aw+=D
		else:	
			Aw+=(D-Bw)
	else:
		Bw+=(Aw-(C-Ab))
		Bb+=Ab
		Aw-=(C-Ab)
		if 0 <= (Bw-D):
			Aw+=D
		else:
			Aw+=Bw
else:
	Bw+=C
	Aw-=C
	if 0 <= (Bw-D):
		Aw+=D
	else:
		Aw+=Bw

print Aw