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:
['2181', '7019', 'l', 'z', 'z', 'y', '1245', '4179', '6951', '7249', '2723']
answer:
l, y, z


question:
['5011', 'l', '925', 'e', 'b', '3077', 'm', '4541', '781']
answer:
b, e, l, m


question:
['4587', '7063', 'h', '291', 'q', 'p', 'w', 'q', 'r', 'd', '9549', '1711', 'v', '5813', '6991', 's', '1881', 'i', 'w', '1117', '5927', 'd', '119', '5991', '3807', 'g', '3801', '361', '9531', '3459', '931', 'u', 'p', '9215', 'z', 'v', 'i', 'q']
answer:

d, g, h, i, p, q, r, s, u, v, w, z