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:
['6027', 'v', 'b', 'l', '7853', 'r', 'y', '2919', '3831']

Ex Output:
b, l, r, v, y


Ex Input:
['9925', 'f', '6149', 's', 'd', 's', '75', '8577', '2319', 'b', '3769', '5211', 'q', 'm', '8127', 'f', '3801']

Ex Output:
b, d, f, m, q, s


Ex Input:
['v', '279', '7861', 'e', 'u', '8071', 'm', 'a', 'k', 'd', 'j', '6235']

Ex Output:

a, d, e, j, k, m, u, v