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: ['6209', 'x', 'j', 'w', '7965', '4905', '6297', '4291', '7183', 'a', 'l', '5267', 'r', '5935', 'a', '7865', 'h', 'p', '6117', 'a', 'y', 'y', 't', 'v', '7271', 'e', 'e', 'z', 'i', 'l', '4731', '2059', 'm', '5703', 'k', 'f', '8125', 'e', '7569', 'r', '2287', '593']

Answer: a, e, f, h, i, j, k, l, m, p, r, t, v, w, x, y, z


Question: ['a', '3281', '9123', '5443', 'w', 'w', 'p', '9275', 'v', 'm', '3549', 'l', 'y', 'l']

Answer: a, l, m, p, v, w, y


Question: ['j', '5231', 't', '545', 'q', 't', '153', '4771', '347', '1243', '7093', '3375', 'f', 'm', '6191', '843', '2629', '431', 'f', 'g', '8549', 'm', '7163', 'l', '5731', 'b', '3201', 'x', 'f']

Answer:
b, f, g, j, l, m, q, t, x