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

get_w = min(d - bw if (d - bw) > 0 else 0, c)
add_b = get_w + (c - get_w - ab if c - get_w > ab else 0)
aw -= add_b
print(aw + min(d, bw + add_b))