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:
['v', '3765', '4065', 'a', '4201', 'f', 'x', '9275', 'q', '9303']
answer:
a, f, q, v, x


question:
['d', 'p', 'k', '9679', 'x', 'j', '7481', '1815', 't', 'w', '6513', 'j', '5079', '5219', 'p', '9545', 'a', '1931', '9973', '8125', '5169', '2791', 't', 'd', '2057', 'e', 'x', 'y', '7409', 'u']
answer:
a, d, e, j, k, p, t, u, w, x, y


question:
['o', '7669', 'u', '6403', '3485', '9357', '5109', '6103', 'q', '5317', 'i', '6855', 'x', '9921', 'w', 'u', '2091', '7121', '3657', 'q', 'h', 'a', '2885', 'n', 'm', '6817', 'h', '2891', 'f', '4853', '85', '3893']
answer:

a, f, h, i, m, n, o, q, u, w, x