instruction:
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:
['9833', '3383', 'h', '3545', '2899', 'y', 'p', 'q', '1901', '3317', '5641', 'v', 'c', 'u', '5521', 'e', '7997', '2439', '5573', '4119', 'k', '8291', '1009', '8253', '405', '233', 'p']
answer:
c, e, h, k, p, q, u, v, y


question:
['1345', 'y', '7221', 'h', 'r', '3255', 'k', 'r', 'j', '8639', '467', 'f', 'k', 'n', 'k', 'j', 'l', 'w', '143', 'w', 'q', '5657', '589']
answer:
f, h, j, k, l, n, q, r, w, y


question:
['y', 'q', 'n', 'q', '399', '4761', 's', 'r', '2519', '9561', '8239', '9817', 'h', '2263', '9855', 'g', 'a', '8487', 'p', 't', '3269', '3557', 'v', 'e']
answer:

a, e, g, h, n, p, q, r, s, t, v, y