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

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

print(ans)