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

tob, toa = map(int,input().split())

al = ["b" for i in range(ab)]+["w" for i in range(aw)]
bl = ["b" for i in range(bb)]+["w" for i in range(bw)]

alr = al[tob:]

bl += al[:tob]
bl.sort()
bl.reverse()

ll = bl[:toa]+alr
print(ll.count('w'))