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:
['747', '5385', '5313', 'p', '9581', 'r', '1339', '3919', 'e', 'e', '8057', '7739', 'i', 'e', '3311', '963', 'g', 'h', '7349', 'y', '1493', 'e', '3055']
answer:
e, g, h, i, p, r, y


question:
['1707', '381', '3957', '7853', '4987']
answer:
-1


question:
['4803', '4757', '8601', '3915', '8169', '7725', '6481', '5843', 'v', '9785', 'q', '1245', '5709', '3949', '6191', 'l', '277', '9431', 'q', 'm', 'n', '5717', 's']
answer:

l, m, n, q, s, v