aw, ab = map(int,input().split())
bw, bb = map(int,input().split())
c, d = map(int,input().split())
toa = 0
tob = 0
ans = 0

if c > ab:
    tob = c - ab
    aw -= tob

bw += tob
bb += c - tob

toa = min(bw, d)

ans = aw + toa
print(ans)