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:
['1345', 'y', '7221', 'h', 'r', '3255', 'k', 'r', 'j', '8639', '467', 'f', 'k', 'n', 'k', 'j', 'l', 'w', '143', 'w', 'q', '5657', '589']
answer:
f, h, j, k, l, n, q, r, w, y


question:
['g', '7517', '3173', 'd', '2143', 'n', '8507', 'l', '8369', '225', 'e', 'l', '9511', 'p', '1317', '5651', 'p', '1125', 't', '739', '6453', 'l', 'g', '8555', '8075', 'x', 's', 'd']
answer:
d, e, g, l, n, p, s, t, x


question:
['k', 'e', 'a', '9243', 'i', 'x', 't', '7675', 'h', '6855', 'u', '8631', '9609']
answer:

a, e, h, i, k, t, u, x