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:
['d', '2359', '6571', 'c', 'n', 'u', '9513', '9321', '1689', 'b', '969', '1823', 'e', 'b', '9147', 's', '1811', 'k', '5443', '8699', '5483', 'v', 'w', 'n', '1215']
answer:
b, c, d, e, k, n, s, u, v, w


question:
['5957', 'd', 'i', 'b', 'e', '5565', 'c', 'i', '2919']
answer:
b, c, d, e, i


question:
['u', '9401', '5333', '7971', 'q', '4811', '9775', '5453', 't', 'j', 'i', '5091', '6427', '5593']
answer:

i, j, q, t, u