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:
['r', 'y', 'c', '3211', '9245', '8459', '8521', '5781', 'w', 's', 'd', '5299', 'a', 'y', 'g', 'm', '6435', '8605', 'e', 'h', '6871', 's', '387', 'l', '5829', 'e', 'd', '9545', '2945', 'k', 'v', 't', '8449', '2199', 'm', '2599', '1489', '6623', 'x', 'l']
answer:
a, c, d, e, g, h, k, l, m, r, s, t, v, w, x, y


question:
['895', '2049', '8839', '1773', 'v', '467']
answer:
v


question:
['r', '8191', 'n', '8025', 'f', '7379', 'd', 'h', '9363', '5135', '77', '9451', '9861', 'n', '5835', 'x', 'h', '5545', 'm', 'v', '2853', 'd', 'k', '3725', '2161', 'h', '2827', '3051', '3671', '3843', 'q', '5403', 'h', 'b', 'o', '5945', 'f', 'a', 'a', 'h', 'd', 's', 'd', '8223', 'z']
answer:

a, b, d, f, h, k, m, n, o, q, r, s, v, x, z