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:
['3995', 'n', 'z', '8389', '7857', '3005', 'i', 'e', '1117', 'z', '8251', 'r', 't']

Ex Output:
e, i, n, r, t, z


Ex Input:
['1971', 'g', 't', 't', 'x', 'q', 'o', 'm', 'h', '9481', '1729', '5527', 'u', '3157', 's', '8795', 'z', 'g', 'i', '1649', 'p', '65', 's', 'u', '6843', 'r', 'l', 'k', 'n', 's', 'm', '7991', 'u', 'a']

Ex Output:
a, g, h, i, k, l, m, n, o, p, q, r, s, t, u, x, z


Ex Input:
['7237', 'n', 'q', 'd', 'x', '7517', '4929', '6437', '2571', '3369', 'q', '6977', '3237', '8431', '4981', '9057', 'j', '7677', '5987', 'v', 'a', 'p', 'v', 'n', 'y', 'u', 'o', '379', '717', '3555', 'h', '3847', 'r', 'y', 'r', 'i', '9419', 'p', 'd', 'j', 'm', '1891', '9729', 'r']

Ex Output:

a, d, h, i, j, m, n, o, p, q, r, u, v, x, y