#coding: utf-8
##yuki_149

aw,ab=map(int,raw_input().split())
bw,bb=map(int,raw_input().split())
c,d=map(int,raw_input().split())

if ab>=c:
 bw=bw
 if bw>=d:
  res=aw+d
 elif bw<d:
  res=aw+bw
elif ab<c:
 bw=bw+(c-ab)
 if bw>=d:
  res=aw-c+ab+d
 elif bw<d:
  res=aw-c+ab+bw

print res