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: ['8815', 'w', '8629', 'y', '3891']
Example Output: w, y

Example Input: ['8975', '7199']
Example Output: -1

Example Input: ['4725', '5177', '7125', 'c', 'g', 'i']
Example Output:
c, g, i

