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]: ['2799', '7519', '345', 'e', 'l', '9369', '4703', '4111']
[EX A]: e, l

[EX Q]: ['7677', '4069', 'b', 'w', '4381', 'b', '5757', '711', '765', '8347', '6547', '9527', '945', '5333']
[EX A]: b, w

[EX Q]: ['d', 'd', 'f', '87', '5215', 'd', '1121', '4229', 'q', 't', 'k', 'd', '285', '5909', 'u', 'z', '1021', '9917', 'v']
[EX A]:
d, f, k, q, t, u, v, z