Definition: 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.
Input: ['v', '1155', '67', 'u', '8643', 'u', '5483', 'c', '8707', 'a', 'q']

a, c, q, u, v