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: ['7677', '4069', 'b', 'w', '4381', 'b', '5757', '711', '765', '8347', '6547', '9527', '945', '5333']

A: b, w
****
Q: ['n', '7489', 'n', 'n', '9787', '7829', 'n', '3481', 'v', 'l', '8927', 'c', 'm', 'd']

A: c, d, l, m, n, v
****
Q: ['t', 'g', 'l', 'h', 'f', '3927', '2167', 'm', '4759', '969', 'd', 'n', '6473', '3463', 'n', '9863', '9187', 'd', '5495', '3925', '8619', '8047']

A:
d, f, g, h, l, m, n, t
****