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:
['a', 'a', 'b']

Ex Output:
a, b


Ex Input:
['c', 'h', '8655', 'r', '7531', 's', 'r', 'w', 'e', 's', 'p', '1709', '5447', 'b', '5855', 'w', 'f', 'i', '7809', 'q', '1975', 'z', '4037', 'k', 'l', 'z', 'g', '9739', '8801', '3405', '6549', '4561', 'd', '1669']

Ex Output:
b, c, d, e, f, g, h, i, k, l, p, q, r, s, w, z


Ex Input:
['k', '2125', '9249', '3721', '597', '3997', '7605', 'd', 'i']

Ex Output:

d, i, k