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:
['k', 'c', 'i']
answer:
c, i, k


question:
['n', 'h', 'j', '5945', '8511', 'y', '7739', '4717', '2483', 'p', '9545', '7647', '9863', '5591', '5393', 'i', '9225', '589', '1497', 'j', 'm', '2397', 'a', 'd']
answer:
a, d, h, i, j, m, n, p, y


question:
['p', '3707', '8089', 'm', '5725', '3239', 'f', 'w', 'n', 'l', 'l', '483', 'y', '2881', '4901', 'd', '7613', '6075', '3853', 'j', 'd', 'd', '8797', 'h', '407', 'l', 'h', '7935', '1153', 'i', '4155', 'w', 's', 'k', 'u', '4621', 'p', '6057', 'w', 'r', 'b']
answer:

b, d, f, h, i, j, k, l, m, n, p, r, s, u, w, y