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:
['9483', '501', 'j', 'k', '3103']
answer:
j, k


question:
['3995', 'n', 'z', '8389', '7857', '3005', 'i', 'e', '1117', 'z', '8251', 'r', 't']
answer:
e, i, n, r, t, z


question:
['t', 'l', 't', '9411', 'j', '3089', 'n', '6623', 't', 'z', '8489', '7025', 'h', 'f', 'l', '1999', 's', 'k', 'r', '3131', 'm', '7891', 'v', '9161', 'k', 'c', 's', 'b', '8969']
answer:

b, c, f, h, j, k, l, m, n, r, s, t, v, z