instruction:
In this task, you are given an input list A comprising of numbers and alphabets. You need to extract and sort the unique alphabets in the list. The alphabets in the input list will only be in lowercase. Return -1 if there is no alphabet in the input list.
question:
['w', '6291', '3939', '9569', 'u', '1635', '3359', '8335', 'n', '2799', '7359', 'k', 'm', '2817']
answer:
k, m, n, u, w


question:
['333', 'b', '261', 'k', 'p', '7861']
answer:
b, k, p


question:
['q', '2769', 'z', '7973', '305', '7245', 'y', '717', '7769', 'q', '8777', '8363', 'o', '9455', 'd', '2915', '523', 'd', '5049', '5469', '5657', '5913', '6605', 'n', '1405', '8415', 'd', 'h', '2735', 'n', 'd', 'w']
answer:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
d, h, n, o, q, w, y, z


