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)
x = min(ab, c)
ab -= x
bb += x
aw -= c - x
bw += c - x
# print(ab, aw, bb, bw)

# D
# print(d)
y = min(bw, d)
bw -= y
aw += y
bb -= d - y
bw += d - y
# print(ab, aw, bb, bw)

print(aw)