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:
['653', '1969', '6235', '6283', 'd', 'e', '465', 'e']
answer:
d, e


question:
['a', 'a', 'b']
answer:
a, b


question:
['7669', '6561', 'z', 'd', 's', 'h', 'o', '1065', '7367', '3275', '5305', '9001', '5183', 'z', '181', '7141', 'r', 'i', '6533', 'n', 'd', 'c', 'p', '1681', 'h', 'x', '57', '5337', '6379', '6823', '1433', 'c', '9395', '4115', 'p', '7625', '5189', '1861', 'e', 'f', '8583', 't']
answer:

c, d, e, f, h, i, n, o, p, r, s, t, x, z