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:
['1985', '729', '169', '1299', 'l', 'z', '6809', '3083', 'w', 'f', '1989', 'z', '889', 'x', 'r', '1601']
answer:
f, l, r, w, x, z


question:
['v', 'l', '9349', 'u', 'c', '8631', 'a', '1095', '4149', 's', 's', 'd', 'u', '8681', '6713', '357', '1299', '247', 'v', '2737', 's', '615', '7929', 'f', '3669', 'p', 'z', 'v', '5561', '8403', '795', 'l', '9525', 'j', '7437', '6681', 'q', '2845', 'w', 'w', 'q', 'q', '8985', '5811']
answer:

a, c, d, f, j, l, p, q, s, u, v, w, z