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]: ['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]: ['9351', 'v', 'h', 'z', 'g', 'f', 't', 'q', 'g', 'o', '4073', 'n', '6149', '1735', '157', 'm']
[EX A]: f, g, h, m, n, o, q, t, v, z

[EX Q]: ['u', 'o', '9987', 'v', 'z', '2461', 'q', '3159', 'n', 'k', 'r', '9961', 'w', 'f', '4419', '3261', '7381', 'j', 'a', '2975', 'o', 'i', 't', 'w', '3899', '3519', 'y', '3183', 'e']
[EX A]:
a, e, f, i, j, k, n, o, q, r, t, u, v, w, y, z