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:
['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:
['2593', '1835', '5089', 'v', '9723', 'f', '9279', '4257', '2175', '655', 'q', 's', 'v', 'j', 'm', '4471', '6419', '1685', '2793', 'x', '509', 's', '4833', '2125', 'b', '6379', '1075']
answer:
b, f, j, m, q, s, v, x


question:
['j', 'i', 'w', 'r', 't', '7087', '4547', 'a', 'i', '6699', 'e', 'h', 'v', '4215', 'j', '6151', '9765', 'i', '9073', 'm', '3367', 'c', 'd', 'x']
answer:

a, c, d, e, h, i, j, m, r, t, v, w, x