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:
['8381', 'j', '761', '5431', '7601', 'd', '4339', '1479', 'b', 'x', 'f', 'w', '2437', '7725', '6385', '411', 'w', 'w', 'i', '2769', '5709', '5703', 'k', '5301', '6503', '7833', 'y', '3813', '7061', '5531', 'n', '2251', 'y', '8941', '8481', 's', 't', 't', '3345', 'k', '1545']
answer:
b, d, f, i, j, k, n, s, t, w, x, y


question:
['3307', 'r', '2665', '3453', 'f', 'd', 'v', '3801', '3153', '3137', 'y', 'i', '9681', 'k', '9253', 'y', 'i', '8631', '2375', '5131', 'r', 'z', '8645', '595', 's', '6749', '2665', '709', '8203']
answer:
d, f, i, k, r, s, v, y, z


question:
['2367', '107', 'k', 'h', 'r', 'z', 'f', 'u', 'r', '3263', '3367', 'c', 'k', '4949', 'o', 'c', '3425', 'q', 'n', 'k', 'w', '5019']
answer:

c, f, h, k, n, o, q, r, u, w, z


