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]: ['d', '771', '4193', 'e', '1537', 'a', 'q']
[EX A]: a, d, e, q

[EX Q]: ['4641', '2881', 'c', '4827']
[EX A]: c

[EX Q]: ['8567', '6023', 'j', 'w', 'd', '8023', 't', '9805', 'd', '5675', '9127', 'r', 'i', 't']
[EX A]:
d, i, j, r, t, w