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:
['7187', '7081', 'j', 'i', '3725', '6333', 'h', 'f', '6639', 'r', 'n', '3559', '2785']
answer:
f, h, i, j, n, r


question:
['d', 'a', '6931', 'c', 'u', 'z', '9713', 'v', 'm', 'e', 'k', 'o', '9705', 'a', '5373', 'c', '2983', '8097', 'h', '3039', 'g', 'f', 'n', 'v', '853', '8227', '7573', 'j', 'h', 'k', 'o', 'k', '8897', 'd', 'g', 'd', 'd', '4039']
answer:
a, c, d, e, f, g, h, j, k, m, n, o, u, v, z


question:
['2947', '5431', 'i', '1047', 'g', 'z', '7183', '6879', '4437', '405', '3389', '111', '5257']
answer:

g, i, z