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]: ['9689', '9727', 't', 'd', '2103', 'c', 'n', '8553', '4559', '7815', 'u', 'l', 'c', 'e', 'u', 'n', '7207', '4875', '7699', 'h']
[A]: c, d, e, h, l, n, t, u


[Q]: ['p', '2923', 'e', 'k', '5433', '605', '5079', 'k', 'p', 'x', '4845', '4099', '6795']
[A]: e, k, p, x


[Q]: ['t', 'u', 'y', 'y', 'b', 'x', 'q', '3713', '2679']
[A]:
b, q, t, u, x, y