# No.149 碁石の移動
Aw, Ab = [int(i) for i in input().split()]
Bw, Bb = [int(i) for i in input().split()]
C, D = [int(i) for i in input().split()]

if Ab < C:
    Aw -= C - Ab
    Bw += C - Ab

if Bw >= D:
    Bw -= D
    Aw += D
else:
    Aw += Bw

print(Aw)