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]: ['333', 'b', '261', 'k', 'p', '7861']
[A]: b, k, p


[Q]: ['6585', 'i', 'p', '5623', '3557', '8011', 'c', '6389', 'h', 'h', 'd', '1823', '5567', 'v', 'p', 'x', 'c', '2161', '3649', 'o', '6227', 'f', '9975', 'd', 'm', '2587', 'o', 't', 'k', '7637', 'm', 'l']
[A]: c, d, f, h, i, k, l, m, o, p, t, v, x


[Q]: ['7729', '9931', 'o', '6709', '5975', 'v', 'g', '5125', '5447', 'q', 'd', '871', 'd', 'c', 'g', '8545', 'q', '8309', '2359', 'p', '5467', '9531', '8559', '8235', '1865', '9139', 't', 'm', 'e', 'e']
[A]:
c, d, e, g, m, o, p, q, t, v