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:
['3019', 'g', 'q', 'u', '611', 'z', '3671', '8119', '1679', 'h', '2631', '655', 'k', '2837', 'e', 'f', 'e', 'f']
answer:
e, f, g, h, k, q, u, z


question:
['r', 'j', '437', 'b', '5223', 'n', 'v', '437', 'd', '8285', 'k', 'j', 'r', 'p', 'n', 'e', 'n', 'j', 'o', '2651', 'j', '6365', 'q', 'q', '2159', 'g', '3641', '7727', 'c', '1197', 's', 't', 'n']
answer:
b, c, d, e, g, j, k, n, o, p, q, r, s, t, v


question:
['1089', 'p', '7169', 'e', '1681', '8755', '9561', 'x', '9431', '3047', '9671', 's', '8597', 'e', 'g', 'e', '1857', '883', 's']
answer:

e, g, p, s, x