MX = 10000000000
a, b, c, x, y, z, l = map(int, input().split())
ans = MX
for i in range(0, x+1):
for j in range(0, y + 1):
for k in range(0, z + 1):
l2 = a * i + b * j + c * k
if l2 >= l and i + j + k < ans:
ans = i + j + k
print(0 if ans == MX else ans)