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: ['y', 'p', 'q', '2157', 'b', 'w', '8875', 'k', 'i', 'd', '9743', '4941', 'b', 'p', '9941', '495', 'h', 'i', '839', 'c', 'h', 'f', 'b', 'a', 'k', 'z', '7549', '4149', 'h', 'j', '1947', 't', 'f', 'c', '1243']

Answer: a, b, c, d, f, h, i, j, k, p, q, t, w, y, z


Question: ['s', '2507', '3091', 'g', '7643', '2573', 'w', 'r', '1977', 'q', 'c', 'j', '1335', '9671', '7317', '567', '2041', '5777', 'w', 'm']

Answer: c, g, j, m, q, r, s, w


Question: ['t', 'e', '7061', 'y', 'c', '7647', '9421', 'z', '3531', 'm', '3741', '2823', 'w', '197', '8007', 'b', 'n', 'e', '2137', '349', 'z', '3065', '4763', '9693', 's', 'b', '3135']

Answer:
b, c, e, m, n, s, t, w, y, z


