Detailed Instructions: 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.
Q: ['6877', '6605', 'l', '2213', 'm', 'p', '445', 'l', 's', 'b', '6607', '2639', 'y', 'd', 'm', 'o', '6419', '489', 'k', '6631', '8349', '5955', '9041', '3127', 'a']
A:
a, b, d, k, l, m, o, p, s, y