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: ['w', '6291', '3939', '9569', 'u', '1635', '3359', '8335', 'n', '2799', '7359', 'k', 'm', '2817']

A: k, m, n, u, w
****
Q: ['7591', '1403']

A: -1
****
Q: ['1593', 'p', 'v', '2409', 'n', '5397', '3059', '465', '5175', '7875', 'y', '633', 'c', '3413', '5495', 'r', 'e', '7189', 'q', '7319', '5385', '5645', 'v', 'f', 'r', '3093', '4765', 'a', '8719', 't', '1963', '6329', '145']

A:
a, c, e, f, n, p, q, r, t, v, y
****