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:
['n', '7489', 'n', 'n', '9787', '7829', 'n', '3481', 'v', 'l', '8927', 'c', 'm', 'd']

Ex Output:
c, d, l, m, n, v


Ex Input:
['9689', '9727', 't', 'd', '2103', 'c', 'n', '8553', '4559', '7815', 'u', 'l', 'c', 'e', 'u', 'n', '7207', '4875', '7699', 'h']

Ex Output:
c, d, e, h, l, n, t, u


Ex Input:
['9155', 'g', '9745', 'k', 'o', 'b', '1049', 'd', '3297', 'r', '6129', 'x', 'x', '1021', '5365', '1167', '2597', '7909', '6189', '2879', '3939', '7639', 'h', 'r', '2937', '8913']

Ex Output:

b, d, g, h, k, o, r, x