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:
['d', '1989', '6365', 'y', 'm', '1245', '7539', 'm', '3787', '6987', 'e', 'e', 'y', '9577', 'b', '5', '8179', 'x', '2853', '6337', 'w', 'f', 'b', 'q', '563', '6077', '1133', 'x', '6045']
answer:
b, d, e, f, m, q, w, x, y


question:
['x', 'n', 'k', 'a', 'k', 'd', '587', '6231', 'w', 'f', 'a', 'r', 'f', 'u', '5903', 'm', 'f', 'a', 'n', '2443', '3989', '7429', '1559', '4305', '8527', 'i', 'h', '9155', '1879', 'k', '7523', 'd', 'b', 'b', 'c', '6355', '9361']
answer:

a, b, c, d, f, h, i, k, m, n, r, u, w, x