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:
['c', 'h', '8655', 'r', '7531', 's', 'r', 'w', 'e', 's', 'p', '1709', '5447', 'b', '5855', 'w', 'f', 'i', '7809', 'q', '1975', 'z', '4037', 'k', 'l', 'z', 'g', '9739', '8801', '3405', '6549', '4561', 'd', '1669']

Ex Output:
b, c, d, e, f, g, h, i, k, l, p, q, r, s, w, z


Ex Input:
['6463', '871', '5781', '283', '9653', 'f', '9661', '3365', '2889', '5499']

Ex Output:
f


Ex Input:
['8209', 'e', 'l', '9953', '391', '6929', '4219', 'k', '1009', 'u', '2625', 'f', 'v', '3569', '763', '609', '9923', 'g', 'q', '3741', 'f', 'w', '1863', 'y', 'w', 'p', '1505', 'i', '1', '3669', '3341', 'j', '4707', '4803', 'x', 'p', '4995', '1305', 'r', '5685', 'h', 'l', 'd', 'v']

Ex Output:

d, e, f, g, h, i, j, k, l, p, q, r, u, v, w, x, y