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]: ['h', 'g', 'j', 'i', 'y', '7799', 'y', 'e', 'y', 'e', '6757', '3349', '1213', '191', 'd', '2149', '849', '8325', 'b', '6087', 'w', '7211', '7801']
[A]: b, d, e, g, h, i, j, w, y


[Q]: ['8315', 'b', '4333', 'f', '6507', '6211', '3475', 'c', 'e', '8039', '661']
[A]: b, c, e, f


[Q]: ['3151', '2739']
[A]:
-1