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', 'p', 'x', '2337', 'q', 'e', 'u', '8723', '3021', 'f']

e, f, p, q, u, w, x