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:
['2329', 'i']

Ex Output:
i


Ex Input:
['6643', '6757', 'h', '1033', 's', 'c', '2003', 'p', '5483', 'f']

Ex Output:
c, f, h, p, s


Ex Input:
['k', 'k', 'm', '7755', '6949', '5581', '463', '9875', '8525']

Ex Output:

k, m


