h, w, la, lb, ka, kb = map(int, input().split())

ans = h + w
b = 0
for a in range(h, 0, -1):
  while b < w:
    if min(h, a * la) * min(w, b * lb) + a * ka + b * kb >= h * w:
      ans = min(ans, a + b)
      break
    b += 1

print(ans)