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: ['3191', '2655', '239', '2585', '3369', '7815', '5919', '8269', '5633', 'x', '8085', '2909', 'y', '2465', 'i', '1579', 'u', '2371', 'l', '1949', '51', 'e']

Answer: e, i, l, u, x, y


Question: ['z', '8763', '6399', '45', '6731', 'v', '441', '4763', 'u', '8741', 'r', '9143', 'd', 'p', '2241', 'y', '6523', 'y', 'w', '6771', 't', 'r', '9239', '295', 'z', '461', 'b', '9217', '2597', '1249', 'r', 'i']

Answer: b, d, i, p, r, t, u, v, w, y, z


Question: ['2985', '6149', 'b', 'e', 'd', '2509', '4619', 'z', 'c', 't', '6323', 'd', '171', 'u', 'e', 'v', '6179', 'p', '4173', 'b', 'q', 'w', 'v', 'r', '3251', '7437', 'c', '3857', '5783', 'm']

Answer:
b, c, d, e, m, p, q, r, t, u, v, w, z