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: ['p', 'g', 'e', '3887', '9053', '8781', '2871', 'd', '5733', '6649', '5775']

d, e, g, p