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

ans = 1 << 60
b = w
for a in range(h + 1):
    while b >= 0 and min(h, a * la) * min(w, b * lb) + a * ka + b * kb >= h * w:
        ans = min(ans, a + b)
        b -= 1
print(ans)