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

def f(x, y):
    return min(h, x * la) * min(w, y * lb) + x * ka + y * kb

ans = 1 << 60
for x in range(h + w + 10):
    l, r = 0, h + w + 10
    if f(x, l) >= h * w:
        ans = min(ans, x)
    else:
        while r - l > 1:
            mid = (l + r) // 2
            if f(x, mid) >= h * w:
                r = mid
            else:
                l = mid
        ans = min(ans, x + r)
print(ans)