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', '4655', 'm', 'l', '4371', 'o', '5331', '5469', 'j', 'u', '4915', 'v', 'i', 'f', 'j', '6139', 'y', '2423', '1271', '2289', '5565', '7561', '9697', 'e', 's', 'u', '9581', 'y', '6095', '5047', '625', '9047', 'd', 's', '8307', '3615', '8145']
answer:
d, e, f, i, j, l, m, o, r, s, u, v, y


question:
['q', 'c', 'o', 'e', 'n', 'q', 'w', '9475', 'w', '863', 'r', '2219', '3483', '5035', '8209', '7957', 'b', '3735', '1423', 'l', '3409', '7639', 'd']
answer:
b, c, d, e, l, n, o, q, r, w


question:
['d', '643', '4543', 'y', 'e', 'a', 'e', 's', '5703', 'm', '7791', 'm', 'j', 'w', '7565', 's', 'j', '735', '4491', 'y', '475', 'l', 'u', 'n', '6221', '9319', '5705', '4939', 'f', 'o', '733', '2033', 'l']
answer:

a, d, e, f, j, l, m, n, o, s, u, w, y