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.

[EX Q]: ['2799', '7519', '345', 'e', 'l', '9369', '4703', '4111']
[EX A]: e, l

[EX Q]: ['2181', '7019', 'l', 'z', 'z', 'y', '1245', '4179', '6951', '7249', '2723']
[EX A]: l, y, z

[EX Q]: ['2509', '3889', '9515', 'e', 'a', '4579', 'a', 'b', '2125', 'b', '6017', 'z', 'y', '6353', '3593', '2297', 'k', '2411', 'i', '4285', '5609', 'd', '9351', 'n', '6477', 'w']
[EX A]:
a, b, d, e, i, k, n, w, y, z