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]: ['5075', '9169', '4659', '7605']
[EX A]: -1

[EX Q]: ['l', '6313', '3199', 'w', '249', '8747', '7391', '3871', '173', 'x', 'o', '8647', '4413', '3645', '6123', '701', 'q', '2147', '4289', '7333', '533']
[EX A]: l, o, q, w, x

[EX Q]: ['8885', '5013', '9647', '4207', 'u', 'b', 'y', '8349', 'l', '4903', 'z', 'e']
[EX A]:
b, e, l, u, y, z