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]: ['5011', 'l', '925', 'e', 'b', '3077', 'm', '4541', '781']
[A]: b, e, l, m


[Q]: ['a', '3281', '9123', '5443', 'w', 'w', 'p', '9275', 'v', 'm', '3549', 'l', 'y', 'l']
[A]: a, l, m, p, v, w, y


[Q]: ['f', 'u', '3859', '5717', 'n', 'o', '4275', 'p', 'p']
[A]:
f, n, o, p, u