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: ['x', '4283', 'n', 'b', 'g', 'p', '8305', '7781', '5907', 's', '1305', 'w', '8623', 'o', 'c', 'u', '1839', '2869', '7537', 'y', '2395', '5309', 'e', '4059', 'l', '6647', 'p', '9717', 'y', 'y', '3769', '2527', '2981', '5255', '4063', 'j', '4843', 'j', '9355', 'z']

Answer: b, c, e, g, j, l, n, o, p, s, u, w, x, y, z


Question: ['n', 't', '2901', '9697', 'a', 'j', 'x', 'a', '4437', '2255', '2177', 's', '3173', 'j', 't', '5713', '4091', '4253', '5553', 'i', '4533', 'i', 'e', '6899', 's', '3541', '2139', '2705', 'm', 'u']

Answer: a, e, i, j, m, n, s, t, u, x


Question: ['n', '2515', '2361', 'i', 'b', 't', '4873', 'q', '565', 'd', 'x', 'c', '9555', 'v', '1961', 'e', '6983', 'i', 'z', 'q', '265', '4497', '7703', '7243', '5977', '2367', 'n', '6589', 'l', 's', 'x', 'p']

Answer:
b, c, d, e, i, l, n, p, q, s, t, v, x, z