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: ['1063', 'f', 'm', 'i', 'x', 'i', 'd']

Answer: d, f, i, m, x


Question: ['7417', '2597', '2633', '7721', 'v', 'l', 'p', '4389', 'l', '3965', '6279', 'm', 'v', 'o', 'd', 'o', 'h', 'd', 'r', 'e', '8993', '2711', 'o', 'q', '1399', 'i']

Answer: d, e, h, i, l, m, o, p, q, r, v


Question: ['6411', '4255', 'x', 'f', 'q', 'q', '359', '8621', 'r', 'w', 'd', '665', '8481', 'q', 's', 's', '861', '6491', '1107', 'n', 'e', '3733', '5887', '6983', '4439', '5385', 't', '803', '2145', 'k', 't', '1621', '3083']

Answer:
d, e, f, k, n, q, r, s, t, w, x