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: ['u', 'w', '6119', 'l', '861', 'd', 'd', '9407', 'c', 's', 'p', '9643', '5675']

c, d, l, p, s, u, w