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.

Q: ['1429', '7273']

A: -1
****
Q: ['l', 'i']

A: i, l
****
Q: ['6437', '2739', '8419']

A:
-1
****
