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:
['277', '8697', 'q', '2023', '5723', 'm', '8673', 'f', 'z', 'z', 'a', '9875', 'p', 'x', 'l', 'z', 'x', '619', '6509', 's', '2067', '571', 't']
answer:
a, f, l, m, p, q, s, t, x, z


question:
['f', '165', 'm', '9975', '9259', '6505', 'a', 'g', 's', '1127', 'h', 'n', 'c', '6475', 'c', '8657', 'a', '4057', 'm', 'y', 'w', 'm', '6567', '7297', '285']
answer:
a, c, f, g, h, m, n, s, w, y


question:
['f', '6069', 's']
answer:

f, s