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: ['a', 'a', 'b']
Example Output: a, b

Example Input: ['2161', '8009', '3057', 'r', '3897', 'd', 'j', '2727', 'b', '3231', 'i', '9227', '393', '5799']
Example Output: b, d, i, j, r

Example Input: ['8271', '2439', '5689', 'c', '8955', '331', '3651', 'b', 'y', 's', 'z', '7027', '3985', '9915', 'u']
Example Output:
b, c, s, u, y, z