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:
['9923', 'x', '1901', 'v', '1459', '7503', '3829', '4929', 'k', 'c', '3329', '8793', 'n', 'a', '7249', 'b', 'l', 'l', 'm', 'p', 'b', 'a']

Ex Output:
a, b, c, k, l, m, n, p, v, x


Ex Input:
['q', '9033', 'p', 'z', '1743', '247', '967', '445', '9849', 'f', '9113', 'b', 'g', '6041', 'j', '927', 'i', 'p', '6821', 'q', '6701', 'f', 'j', 'o', 'y', 'c', '7981', 'b']

Ex Output:
b, c, f, g, i, j, o, p, q, y, z


Ex Input:
['x', '2319', 'h', 'd', '9903', '5923', 'y', '8545', '2735', 'w', 'a', '2563', 'g', 'q', '1447', '2517', '4185', 's', '7083', '3735', 'k', 'n', 'f', 'e', '3675', '5757', '3801', 'k', '5931', 'g', '9145', 'k', '4457', '6657', 'h', 'r', '3089', '6343', 'z', '1063', '7955', 'w', '1219', 'e', 's']

Ex Output:

a, d, e, f, g, h, k, n, q, r, s, w, x, y, z