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.
--------
Question: ['9925', 'f', '6149', 's', 'd', 's', '75', '8577', '2319', 'b', '3769', '5211', 'q', 'm', '8127', 'f', '3801']

Answer: b, d, f, m, q, s


Question: ['x', 'j', '9747', 'i', '2015', '3505', 'q', 'n', 'h', '3011', 'u', '8043', 'j', 'f', 'd', 'a', 'p', '5817', 'l', 'q', '2275', 'n', '7085', '5373', 'l', 'g', 'b', '8043', '3085']

Answer: a, b, d, f, g, h, i, j, l, n, p, q, u, x


Question: ['165', 'e', 'k', '8263', 'f', 'e', '8891', 'w', '9657', '3743', 'a', 'y', '6627', '71', '2069', '1891', '3417', 'v', '5129', 'v', '4883', 'h', 'x', '6457', '8581', 'i', '6663', 'g', 'w', 'l', 'u', '181']

Answer:
a, e, f, g, h, i, k, l, u, v, w, x, y