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:
['f', '9203', 'w', 'f', '3751', '8095', '1319', 'f', '3017', 'r', 'y', '8221', '2715', '9959']
answer:
f, r, w, y


question:
['j', '1733', 'p', '6741', '7933', '8943', '733', 'x', '1107', 'z', '1719', '7653', 'y', 'z', '6563', 'p', '4615', 'j', '4489', 'h', 'w', 'y', 'p', 'c', '7949', 'k', 'm', 'r', '9427', '7243', '9777', 'j', '323', '4095', 't']
answer:
c, h, j, k, m, p, r, t, w, x, y, z


question:
['v', 'y', '2645', '2253', 'c', '599', '2071', 'a', 'a', 's', '3087', '5307', '4105', '3465', '5689', 'u', '9963', '373', '2225', 'x', '6765', '3637', 'e', '7211', '6733']
answer:

a, c, e, s, u, v, x, y