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.

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


[Q]: ['d', '1989', '6365', 'y', 'm', '1245', '7539', 'm', '3787', '6987', 'e', 'e', 'y', '9577', 'b', '5', '8179', 'x', '2853', '6337', 'w', 'f', 'b', 'q', '563', '6077', '1133', 'x', '6045']
[A]: b, d, e, f, m, q, w, x, y


[Q]: ['5519', '3499', 'o', 'f', '7875', '4165', 'g', 'v', '3037', '4605', '9379', '7431', 'x', '3435', '4933', '6003', '6961', 's', 'm', 'z', '4655', 'v', '1405', '5825', 'd', '281', '245', '9433', 'g']
[A]:
d, f, g, m, o, s, v, x, z