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:
['895', '2049', '8839', '1773', 'v', '467']
answer:
v


question:
['i', '9215', 'n', 'p', '4815', '8757', 'm', '1755', 'c', 'z']
answer:
c, i, m, n, p, z


question:
['o', 'i', '221', '7009', 'h', '3141', '717', '7361', 'd', 'c', '109', '1569', '7721', '3643', 's', 'y', '4857', '3735', '7315', '6131', '3489', 'l', 'k', '7999', 'h', 'c', 'j', '5771', '2705', 'j', 'h', 'x', 'b']
answer:

b, c, d, h, i, j, k, l, o, s, x, y