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]: ['8821', '9833', 'l']
[A]: l


[Q]: ['c', 'e', '6509', '1295', 'u', '5445', '1731', '3049']
[A]: c, e, u


[Q]: ['k', 'j', '6481', 'k', 'a', 'h', 't', '377', 't', '7277', 'y', '4189', '6927', 'd', '4535', 'r', 'e', 'd', '1353', '8161', 't', 'g', '8745', 'z']
[A]:
a, d, e, g, h, j, k, r, t, y, z