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: Consider Input: ['8975', '7199']

Output: -1


Input: Consider Input: ['4925', 'i', 'q', 'k', '7615', 'r', '7217', 'o', '8097', '9151']

Output: i, k, o, q, r


Input: Consider Input: ['r', 's', '825', '4417', 's', '9011', '5581', 'r', 'a']


Output: a, r, s