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]: ['s', 'j', '6779', '1535', 'd', 'e', 'u', '3023', '241', '9115', 'h', '8003', '3755', 'q', 'm', '2725', 'x', 'y', 'n', 'm', 'j']
[A]: d, e, h, j, m, n, q, s, u, x, y


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


[Q]: ['h', '8759', '2481', 'p', 'j', '4427', 's', 'p', 'l', 'j', '2129', 'v', 'j', '2921']
[A]:
h, j, l, p, s, v