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.

Example Input: ['m', '8127', '7519', '4543', '2809', '9855', 'n', '6241', 'w', 'w', 'q', 'w', 'p', '8599', '7819', '3817', 'm', 'q']
Example Output: m, n, p, q, w

Example Input: ['9947', '3353', '8643', '4621', '4857', 'y', '7075', 'c', '8911']
Example Output: c, y

Example Input: ['n', 'u', '3993']
Example Output:
n, u