AW,AB=map(int,input().split())
BW,BB=map(int,input().split())
c,d=map(int,input().split())

if c<=AB:
    AB-=c
    BB+=c
else:
    k=c-AB
    AW-=k
    BW+=k
    BB+=AB
    AB=0

if d<=BW:
    BW-=d
    AW+=d
else:
    k=d-BW
    BB-=k
    AB+=k
    AW+=BW
    BW=0

print(AW)