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:
['8235', 't', '1695', '9899', '3633', 't', '1823', 'r', 'x']

Ex Output:
r, t, x


Ex Input:
['2349', 'p', 'a', '435', 'y', 'h', '3249', 'o']

Ex Output:
a, h, o, p, y


Ex Input:
['l', 'u', '3901', '341', '5801']

Ex Output:

l, u