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: ['w', '7485', '5125', '3483', 't', 'q', 'k', '1205', 'm']

k, m, q, t, w