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]: ['6769', '1057', '1021', 'n', '8231', '9173', '8123', 'a', '6053', 'q', 'y', '883', 'r', '1215', 'x', 'o', '9531']
[A]: a, n, o, q, r, x, y


[Q]: ['j', '917', 'w', 't', '8873', '1431', '8059', '7041']
[A]: j, t, w


[Q]: ['j', '3301', '5105', 'o', '4821', '3167', '2171', '5933', 'g']
[A]:
g, j, o