instruction:
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:
['4857', 'z', '313', '7813', '9935', 'o', 'w', 'i', 'x', 'o', 'e', 's', 'a', 'p', 'i', 'v', 'x', '6743', 'p', '435', 'u', 'a', 'h', '607', '2491', '6159', 'u', '7761', '6197', '3449', '3459', 'e', 'g', '8731', '335', '2883', '3941', 'n', '1881', 'y', 'j', '8189', 'k', '7593', '2747']
answer:
a, e, g, h, i, j, k, n, o, p, s, u, v, w, x, y, z


question:
['4417', 'x', '4641', '885', '8485', 'd', '7057', '8519', 'm', 'i', 'l', '4627', '3069', 'v', '5011', 'u', '6673', 'h', '4541', 'j', '2337', '8175', '4797', 'f', '9109', 'q', 'q']
answer:
d, f, h, i, j, l, m, q, u, v, x


question:
['g', 'h', 'g', 'g', 's', 'h', '2849', '2705', '1185', 'x', '5789', '8221', 'e', 'x', 'g', 'b', '4903', 'q', '1563', 'r', 'k', 't', '9047', 'p', 'p', '9397', 'u', '7473', 'f', 'o', 'y', '1957', '1039', '9905', 'i', '4829', 'q', 'w', 'k', 'p', 't', '563', 'g', 'l']
answer:

b, e, f, g, h, i, k, l, o, p, q, r, s, t, u, w, x, y