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:
['s', 's', '6581', 'e', '7355', '1315']
answer:
e, s


question:
['w', '491', 'x', 'u', 'z', 'q', '5411', '7629', '8261', '8629', '1441', '5139', 's', 'm', '6463', 'u', 'z']
answer:
m, q, s, u, w, x, z


question:
['5841', '6233', '2529', 'l', 'b', '953', '2123', 'n', '1651', '483', '2593', '5967', 'v', 'h', '589', '441', '5321', 'q']
answer:

b, h, l, n, q, v