Definition: 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.
Input: ['6167', '5053', '4449', 'u', '5825', '3357', '4357', 'k', '8585']

k, u