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:
['u', '635', '5249', '9457', 's', '9317', '9407', 'l', 'w', '9705', 'k', '429', '5489', 'e', 'd', '2457', 'o', '4665', '1675', 'l', 'y', 's', 'o', 't', '4285']
answer:
d, e, k, l, o, s, t, u, w, y


question:
['v', '6635', '5395', '3263', '4391', 'h', '1521', 'f', '9861', '6125', '1673', '3679', '8681', '4967', 'f', 'a', 'c', 'k', 'n', '4155', 'e', 'm', 'i', '1699', 'r', 'f', 'u', 'r', '3451', 'v', '7239', 'o', '4359', 'l', 'a', '2925']
answer:
a, c, e, f, h, i, k, l, m, n, o, r, u, v


question:
['519', 'j', '3643', '4853', '5689', '6809', 'z', 'r', 'b', 'u', '4443', 'n', '2655', 'g', '9641']
answer:

b, g, j, n, r, u, z