Aw, Ab = [int(x) for x in input().split()]
Bw, Bb = [int(x) for x in input().split()]
c, d = [int(x) for x in input().split()]

if c > Ab:
    sub = c - Ab
    Aw -= sub
    Bw += sub
Aw += min(Bw, d)

print(Aw)