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]: ['q', 'g', 's', 'g', 'z', '987', '777']
[EX A]: g, q, s, z

[EX Q]: ['3147', '9807', '5313', '6311', '737', '1555', '5803', '3437', '5665', '3973', 'o', 'f', '7871', '1721', '7833', '2933', 'b', 'b', 'n', 'm', 'k']
[EX A]: b, f, k, m, n, o

[EX Q]: ['9135', '3329', 'x', '3197', '5239', 'p', '1583', 'e', '9477', 'a', '935', 'r', '3317', '4755', 'u', 'j', '7669', '4789', 'j', 'e', '6933', '6091', 'a', 'o', 'q', '801', '305', '2641', 'd', 'd', 'q', 'm', 'n', 'w', 'r', 'o', 'u', 'p', 'g', '4805', '7911', 'd', 'u']
[EX A]:
a, d, e, g, j, m, n, o, p, q, r, u, w, x