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:
['3995', 'n', 'z', '8389', '7857', '3005', 'i', 'e', '1117', 'z', '8251', 'r', 't']
answer:
e, i, n, r, t, z


question:
['i', 's']
answer:
i, s


question:
['6775', '4729', 'q', '9091', 'z', 's', 'p', '2427', 'e', '8973', 'w', '1243', 'c', 'k', 'z', 'h', 'm']
answer:

c, e, h, k, m, p, q, s, w, z


