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.
Problem:['6437', '923', '8747', 'd', 'g', 'i', 's', '6009', 'w', '2585', 'i', '6005', '183', 'i', '4681', 'v', '6667']
Solution:
d, g, i, s, v, w