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:
['7911', '7175', 'y', '9173', 'y', '2529', '831', 'k', '7197', 'j', '2343', 'i', 'b', '6799', '5987', '7277', 'n', 'x', 'h', '7209', 'l', 'd', 'm', 'e', '2277', '8909', 'x', '5361']

Ex Output:
b, d, e, h, i, j, k, l, m, n, x, y


Ex Input:
['2527', '9123', '8717']

Ex Output:
-1


Ex Input:
['9515', 'c', 'h', '9125', '891', 'j', '7343', '831', 'w']

Ex Output:

c, h, j, w