def check(h, w):
    yoko = min(H, h * LA)
    tate = min(W, w * LB)
    nokori = H * W - yoko * tate
    return h * KA + w * KB - nokori >= 0 

H, W, LA, LB, KA, KB = map(int, input().split())
ans = 10 ** 18
for h in range(H + 1):
    yes = 10 ** 6
    if not check(h, yes):
        continue
    if check(h, 0):
        ans = min(ans, h)
        continue
    no = 0
    while yes - no != 1:
        mid = (yes + no)//2
        if check(h, mid):
            yes = mid
        else:
            no = mid
    ans = min(ans, h + yes)
print(ans)