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]: ['w', '1367', '5389', '9515']
[A]: w


[Q]: ['d', '4377', '9271', '8053', '9519']
[A]: d


[Q]: ['q', '8553', 'k', 'b', '9161', 'o', 'z', '1615', '6539', 'z', 'b', '1789']
[A]:
b, k, o, q, z