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.

[EX Q]: ['u', 'd', '4193', '5687', 'p', 'r', '7787', 't']
[EX A]: d, p, r, t, u

[EX Q]: ['c', '1693', 'l', 'u', 'x', '3609', 'h', '4159']
[EX A]: c, h, l, u, x

[EX Q]: ['9829', '57', 'd', 'u', '3857', 'x', '5047', 'h', 'f']
[EX A]:
d, f, h, u, x