#  go
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())
R=C-Ab
if R<0:
    R=0
Aw-=R
Bw+=R
if D>Bw:
    R2=Bw
else:
    R2=D
print(Aw+R2)