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


[Q]: ['l', 'u', '3901', '341', '5801']
[A]: l, u


[Q]: ['1379', '8789', 'q', 'z', '2373', '5871', 'e', '149', '2809', 'k']
[A]:
e, k, q, z