aw, ab = map(int, input().split())
bw, bb = map(int, input().split())
c, d = map(int, input().split())
# print(ab, aw, bb, bw)

# c
# print(c)
abc = max(0, ab-c)
aw -= c-ab
bb += ab
bw += max(0, c-ab)
# print(abc, aw, bb, bw)

# D
# print(d)
aw += min(bw, d)

print(aw)