aw, ab = map(int, input().split())
bw, bb = map(int, input().split())
C, D = map(int, input().split())

# a -> b で、C 個移す
b = min(C, ab)
w = C-b if b < C else 0
ab -= b
aw -= w

bb += b
bw += w
# b -> で、D 個移す
w = min(D, bw)
b = D-w if w < D else 0
aw += w
ab += b

print(aw)