def cookies(k,A): # convert list A to priority queue heapq heapq.heapify(A)

iteration = 0
while any(c < k for c in A) and len(A) > 1:
    mix = heapq.heappop(A) + 2 * heapq.heappop(A)
    heapq.heappush(A,mix)
    iteration += 1


if not all(c >= k for c in A):
    return -1

return iteration