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:
['7799', '8163', '3389', 'x', 'k', 'm', '6085', 'f', '1131']
answer:
f, k, m, x


question:
['7839', '849', '5651', '4275', 'e', '5453', 'h', '2099', '485', 'i', 'm', 'n', '6563', '5675', '4001', 'h', 'm', 'z', '3467', '4237', '5035', '5609', '8475', '5171', 'v', '3883', '8461', '8611', '4853', 'd']
answer:
d, e, h, i, m, n, v, z


question:
['3883', 's', '8341']
answer:

s