Q: 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.
['b', '3983', 'k', 'c', '5969', 'm', '899', 's', 'b', '4981', 'e', '2557', '9453', '2307', '743', 'q', '4279', '4437', '5341', '425', 'b', '3371', '3939', '1769', 'm', '9713', 'e', '1217', 'y', 'c', 'd', 'v', '45', '4649', '2509', 'm', '1505', 'y', '2439', 'c']
A:
b, c, d, e, k, m, q, s, v, y