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]: ['9923', 'x', '1901', 'v', '1459', '7503', '3829', '4929', 'k', 'c', '3329', '8793', 'n', 'a', '7249', 'b', 'l', 'l', 'm', 'p', 'b', 'a']
[EX A]: a, b, c, k, l, m, n, p, v, x

[EX Q]: ['w', '491', 'x', 'u', 'z', 'q', '5411', '7629', '8261', '8629', '1441', '5139', 's', 'm', '6463', 'u', 'z']
[EX A]: m, q, s, u, w, x, z

[EX Q]: ['313', '563', '2217', 'a', '9001', 'x', '2991', 'i', 'u', '3261', '3793', '1959', 'r', '675', 'y', '9979', '291', '5699', '7909', 'b']
[EX A]:
a, b, i, r, u, x, y