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: ['4857', 'z', '313', '7813', '9935', 'o', 'w', 'i', 'x', 'o', 'e', 's', 'a', 'p', 'i', 'v', 'x', '6743', 'p', '435', 'u', 'a', 'h', '607', '2491', '6159', 'u', '7761', '6197', '3449', '3459', 'e', 'g', '8731', '335', '2883', '3941', 'n', '1881', 'y', 'j', '8189', 'k', '7593', '2747']

Answer: a, e, g, h, i, j, k, n, o, p, s, u, v, w, x, y, z


Question: ['w', 'o', 'l', '1857', 's', 'q', 'j', 'e', '5945', 'g', 'l', '9563', 'e', 'u', '7633', '7977', '4943', 'y', '5621', 'f', '1653', 'c', 'l', '2843', '2125', '7731', '5257', '5667', 'b', 'b', '5765', 'a', 't', '8163', '9785', '5385']

Answer: a, b, c, e, f, g, j, l, o, q, s, t, u, w, y


Question: ['q', '3423', '8971', 's', '6385', 's', '1735', 'x', 'h', '4759', 'y', 'p', '6507', '2131', 'm', 't', 'p', '2625', '9269', '5725', '67', '2449', 'u', 'v', '1417', 'c', '1303', '1353', '5877', '2097']

Answer:
c, h, m, p, q, s, t, u, v, x, y