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]: ['l', 'i']
[A]: i, l


[Q]: ['9947', '3353', '8643', '4621', '4857', 'y', '7075', 'c', '8911']
[A]: c, y


[Q]: ['4013', '4051', 'v', 'x', 'a', '649', 'j', '475', '9615', '135', 'n', 'u', 'g', '8317', '889', '9851', 'j', '5631', '1307', '5469', 'h', 'w', 'r', 'w']
[A]:
a, g, h, j, n, r, u, v, w, x