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.

[Q]: ['6463', '871', '5781', '283', '9653', 'f', '9661', '3365', '2889', '5499']
[A]: f


[Q]: ['p', '9641', '8515', '1207', 'd', 'j', '6617', '5529', 'g', 'a', 'o', 'f', 'y', '4993', '4643', '6087', 'n', '3177', 'y', '9471', '1229', '8211', '7079']
[A]: a, d, f, g, j, n, o, p, y


[Q]: ['g', 'k', '2729', '5235', '8001', '9765', '7359', 'c', 's', 'v', 'p', '7019', 'o', 'y', 'l', '1053', '4309', 'e', 'r', 'l', 'i', '9769', '6661', '6549', 'q', 'b', '783', '6833', 'z', '1535', '2153', 'o', 'm', 'u', 'd', 'v', 'a', 'e']
[A]:
a, b, c, d, e, g, i, k, l, m, o, p, q, r, s, u, v, y, z