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:
['2181', '7019', 'l', 'z', 'z', 'y', '1245', '4179', '6951', '7249', '2723']
answer:
l, y, z


question:
['m', '3023', '7413', 'x', '5983', 'n', 'r', '9681', '3853', 'f', '3675', 'e', 'h', '3915', 'u', '2035', '4789', '4105', 'd', 'b', 'b', 'f', 'r', 'k', 'g', '2223', '5493', '2583', 'g', '6653', '5997', 'z', '9725', '8267']
answer:

b, d, e, f, g, h, k, m, n, r, u, x, z