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:
['p', 'f', 'h', '1977', '6221', 'i', 'a', 'l', '5225', '8059', 'c', 'w']
answer:
a, c, f, h, i, l, p, w


question:
['q', 'h', 'q', '7185', 'f', 'l', 'r', '3605', 'x', 'i', 'v', '8789', 'u', 'x', 'x', '8315', 'x', 't', 'h', 'o', '4943', '5827', '7677']
answer:
f, h, i, l, o, q, r, t, u, v, x


question:
['s', 'z', 'd', 'k', '957', '2881', '6725', '327', '1759', 'h', 'p', 'q', 'x', '7395', 't', 'f', 'u', 'm', 'j', '3223', 'e', '1173']
answer:

d, e, f, h, j, k, m, p, q, s, t, u, x, z