def cookies(k, A):
    import heapq

    heapq.heapify(A)
    count = 0
    while not all(i >= k for i in A): # until all cookies are >= k
        if len(A) == 1:
            return -1
        a, b = heapq.heappop(A), heapq.heappop(A)
        c = a + 2 * b
        heapq.heappush(A, c)
        count += 1
    return count