a_w, a_b = map(int, input().split())
b_w, b_b = map(int, input().split())
c, d = map(int, input().split())

if c > a_b:
  a_diff = c - a_b
  a_w -= a_diff
  b_w += a_diff

if d < b_w:
  a_w += d
else:
  a_w += b_w

print(a_w)