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]: ['i', 'x', 'n', 'w', '8915', 'd', 'd', 'd', '6025', '7861']
[A]: d, i, n, w, x


[Q]: ['4927', 'h', 'x', '4719', 'j', 'f', '7797', 'l', 'i', 'q', 'x', 'i', 'k', '3215', 'k', '1625', 'g', 't', 'i', 'w', 'n', '6659', '8355', '831', 'h', '9723']
[A]: f, g, h, i, j, k, l, n, q, t, w, x


[Q]: ['6027', 'v', 'b', 'l', '7853', 'r', 'y', '2919', '3831']
[A]:
b, l, r, v, y