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.

['4213', '3595', '7937', 'y', '5723', 'v', 'b', '7007']
b, v, y

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

['8725', 'q', '9143']

q