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:
['5163', 'n', 'j', '67', '3801', 'n', '7113', 'z', '579', '6885', '8921', 'v', '5481', '5507', 'k', '8403', 'c', '837', 'u', '6341', 'd', 'i', '497']
answer:
c, d, i, j, k, n, u, v, z


question:
['a', '2579', 'f', '6787', '123', '225', '6499', '4419', 'o', '1785', '7981', 'z', 'b', '2441', '2821', 'o', 'k', '2747', 's', 'u', 'q', '3901', '7629', 'k', 'm', 'q', '6577']
answer:
a, b, f, k, m, o, q, s, u, z


question:
['k', '8895', '2619', 'o', 'n', '2037', '569', 'f', '2957', 'f', '4435', '5077', '2995', 'u', 't', '1165', 'y', 'k', '9297', '7717', 't', 'b', '1157', 'e', '6421', 'm', '5929', '1071', '1041', '8915', '6971', '5475', 'f', 'q']
answer:

b, e, f, k, m, n, o, q, t, u, y