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:
['v', 'l', 'v', '7673', '8975', 'u', '2471', '4151', '3615', '1139', 'i', 'z', '8833', 'v', '341', 'l', 'n', 'l', 'd', '9207', '1861', '3901', 'a']

Ex Output:
a, d, i, l, n, u, v, z


Ex Input:
['6709', 't', 'n', 'k', '991', 'a', '8899', '3563', '527', 'm', '4599', '6679', 'm', 'x', 'f', 'o', '3275', 'x', '677', 'b', '3329', '3593', '5183', '5753', 'u', '6045', '2607', 'y', '9873']

Ex Output:
a, b, f, k, m, n, o, t, u, x, y


Ex Input:
['2977', 'g', '801', '2977', 'n', '1713', 's', 'i', 't', 'f', 'd', '697', 'n']

Ex Output:

d, f, g, i, n, s, t