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]: ['4641', '2881', 'c', '4827']
[EX A]: c

[EX Q]: ['7591', '7521', 'm', '1429', 'x']
[EX A]: m, x

[EX Q]: ['u', '9125', 'u', 'q', 'v', '2011', '8023', 'a', 'r', '4275', '1535', 'c', '2143', 'm', 'y', '6241', 'a', 'j', '9483', '1225', '483']
[EX A]:
a, c, j, m, q, r, u, v, y