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]: ['m', '6761']
[A]: m


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


[Q]: ['6813', '7183', 'j', '4115', '3915', '3605', '7853', 'p']
[A]:
j, p


