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]: ['l', 'g', 'd', 'p', '8163', '6643', 'o', 'p', 'm']
[A]: d, g, l, m, o, p


[Q]: ['8815', 'w', '8629', 'y', '3891']
[A]: w, y


[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