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]: ['9483', '501', 'j', 'k', '3103']
[A]: j, k


[Q]: ['3797', '6117', 'x']
[A]: x


[Q]: ['g', '6343', 'p', '3727', '5591']
[A]:
g, p