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.

[EX Q]: ['6769', '1057', '1021', 'n', '8231', '9173', '8123', 'a', '6053', 'q', 'y', '883', 'r', '1215', 'x', 'o', '9531']
[EX A]: a, n, o, q, r, x, y

[EX Q]: ['7155', 'y', '145', '7147', 'u', '8453', 'd', '3693', '6471', '5289', 'n', 'p', '8289', '2929', '199', 'e', '8377', '8937', '5315', 't', 'l', '7715', 'c', 'y', 'f', '9999', 'p', '3655', '5489', 'q', '2321', '9881', '2265', 'n', 'v', '455']
[EX A]: c, d, e, f, l, n, p, q, t, u, v, y

[EX Q]: ['745', '3513', '5571', '513', '1743', 'q', '1193', '5025', 'w', '793', '3025', 'f', '7293', '8681', 'q', '7673', 'x', 'a', '8197', 'p', '4325', 's', '8803', 'k', 's', 'x', '7327', 'o', '3915', 'a', 'q', '3897', 'n', '4461', 'y', '3043', 'x', '5025', '6915']
[EX A]:
a, f, k, n, o, p, q, s, w, x, y