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.

Ex Input:
['4009', 'y', '9077', 'p', 'q', '6711', '6443', '5491']

Ex Output:
p, q, y


Ex Input:
['895', '2049', '8839', '1773', 'v', '467']

Ex Output:
v


Ex Input:
['7591', '1403']

Ex Output:

-1