Aw,Ab = map(int, input().split())
Bw,Bb = map(int, input().split())
c,d = map(int, input().split())

#print([Aw,Ab,Bw,Bb],c)
Bw += max(0,c-Ab)
Aw -= max(0,c-Ab)
Bb += min(Ab,c)
Ab -= min(Ab,c)
#print([Aw,Ab,Bw,Bb],d)
Ab += max(0,d-Bw)
Aw += min(Bw,d)
Bb -= max(0,d-Bw)
Bw -= min(Bw,d)
#print([Aw,Ab,Bw,Bb])
print(Aw)