a1, b1 = map(int, input().split())
a2, b2 = map(int, input().split())
c, d = map(int, input().split())
bb1 = min(b1, c)
aa1 = max(0, c - bb1)
a1 -= aa1
b1 -= bb1
a2 += aa1
b2 += bb1
aa2 = min(a2, d)
bb2 = max(0, d - aa1)
a1 += aa2
b1 += bb2
a2 -= aa2
b2 -= bb2
print(a1)