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]: ['l', 'g', 'd', 'p', '8163', '6643', 'o', 'p', 'm']
[A]: d, g, l, m, o, p


[Q]: ['s', 's', '6581', 'e', '7355', '1315']
[A]: e, s


[Q]: ['q', '8781', 'u', 'l', '7115', '6315', 'z', '9707', 'q']
[A]:
l, q, u, z