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: ['8235', 't', '1695', '9899', '3633', 't', '1823', 'r', 'x']
Example Output: r, t, x

Example Input: ['5971', 'x', 'c']
Example Output: c, x

Example Input: ['o', '6169', '9277', 'k', '87', '683', '6273', '7159', 'p', '1579', '4057', '987', 'm', '6755']
Example Output:
k, m, o, p