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

if Ab >= c:
    Ab-=c
    Bb+=c
else:
    Ab, Bb, Aw, Bw = 0, Bb + Ab, Aw - (c - Ab), Bw + (c - Ab)
#print(Aw,Ab,Bw,Bb)

if Bw >= d:
    Bw -= d
    Aw += d
else:
    Bw ,Aw, Bb, Ab = 0, Aw + Bw, Bb - (d-Bw), Ab + (d-Bw)
#print(Aw,Ab,Bw,Bb)

print(Aw)