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]: ['9117', '1153', 'f', 'b', '9979']
[EX A]: b, f

[EX Q]: ['7073', 'd', 'e']
[EX A]: d, e

[EX Q]: ['v', '2411', '4851', 'a']
[EX A]:
a, v