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: ['5971', 'x', 'c']

A: c, x
****
Q: ['4009', 'y', '9077', 'p', 'q', '6711', '6443', '5491']

A: p, q, y
****
Q: ['5813', '6179', '6179', 'd', 'd', 'c', 'r', 'u', '4701', 'b', '8737', '3403', '1067', 'q', '435', '9461', '7035', 'w', 's', 'w']

A:
b, c, d, q, r, s, u, w
****