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]: ['2409', 'q', 'w', 'e', 'x', '4737', 'w']
[EX A]: e, q, w, x

[EX Q]: ['t', 'u', 'y', 'y', 'b', 'x', 'q', '3713', '2679']
[EX A]: b, q, t, u, x, y

[EX Q]: ['973', 'b', '7835', '621', '5125', 'j', '373', '5473', 'w', '5743', 't', 'f', 'h', '4935', '5987', '1925', 'l', '5023', '275', 'u', 'g', '6665', '9155', 'z', 'h', 'd', '9117', '5555', 'y', '4641', '8931', 'u', '7307', '8589', 'd', '5281', '9815', 't', 'f', 'd', '7721', '7653', '4845', '6751']
[EX A]:
b, d, f, g, h, j, l, t, u, w, y, z