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:
['7417', '2597', '2633', '7721', 'v', 'l', 'p', '4389', 'l', '3965', '6279', 'm', 'v', 'o', 'd', 'o', 'h', 'd', 'r', 'e', '8993', '2711', 'o', 'q', '1399', 'i']
answer:
d, e, h, i, l, m, o, p, q, r, v


question:
['9783', '3185', '8225', 'u', '1123', 'd', '3453', 'i', '7713', '8457', '8609', 'h', '2767', 'e', '7191', '2929', '1089', '393', 'e', 'd', '11', '9329', '683', '1271']
answer:
d, e, h, i, u


question:
['3405', '5757', '8747', '4351']
answer:

-1