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:
['q', 'g', 's', 'g', 'z', '987', '777']

Ex Output:
g, q, s, z


Ex Input:
['n', 't', '2901', '9697', 'a', 'j', 'x', 'a', '4437', '2255', '2177', 's', '3173', 'j', 't', '5713', '4091', '4253', '5553', 'i', '4533', 'i', 'e', '6899', 's', '3541', '2139', '2705', 'm', 'u']

Ex Output:
a, e, i, j, m, n, s, t, u, x


Ex Input:
['3531', '7315', '4091', '8427', 'i', '3653', 'x', 'j', '4545', '1159', '5715', '3745', '8403', '7915', 'p', '293', '8499', 'c', '4873', '1765', 'r', '8559', '6343', 'b', '4841', '2293', '537', '1937', 'f', '2675', '7747', 'f', 'k', '3817', '7039', 'm', 'v', 's', '3571', 'm']

Ex Output:

b, c, f, i, j, k, m, p, r, s, v, x