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: ['c', 'h', '8655', 'r', '7531', 's', 'r', 'w', 'e', 's', 'p', '1709', '5447', 'b', '5855', 'w', 'f', 'i', '7809', 'q', '1975', 'z', '4037', 'k', 'l', 'z', 'g', '9739', '8801', '3405', '6549', '4561', 'd', '1669']

Answer: b, c, d, e, f, g, h, i, k, l, p, q, r, s, w, z


Question: ['j', 'p', '8333', '8079', '4703', '7089', '8859', 'b', 'y', 'g', '7971', '6999', '2011', 'k', 'e', '9609', '4179', '3993', 'u', '3957', '6313', '4229', 'k', '5963', 'e', 'y', 'r', 'e', 'a', '2213', 'e', 'i', 'f', '7979', 'r', 'a', 'h', 'e', 'n']

Answer: a, b, e, f, g, h, i, j, k, n, p, r, u, y


Question: ['6617', 'g', '5983', '1527', '2387', 'j', 'z', '4689', 'f', '1535', '5889', 'u', 'u', 'l', '1407', '1273', '2041', 'k', 'h', '6803', '7291', '9065', '6215', '9365', 'z', 'f']

Answer:
f, g, h, j, k, l, u, z


