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: ['w', '1367', '5389', '9515']

Output: w


Input: Consider Input: ['j', '917', 'w', 't', '8873', '1431', '8059', '7041']

Output: j, t, w


Input: Consider Input: ['4743', 'n', '6151', 'l', '4507']


Output: l, n