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]: ['6027', 'v', 'b', 'l', '7853', 'r', 'y', '2919', '3831']
[EX A]: b, l, r, v, y

[EX Q]: ['231', 'r', '5673', 'j', '589', 'z', '4659', 'a', '3763']
[EX A]: a, j, r, z

[EX Q]: ['u', 'i', '1955', 'v', 'n', '2507', '9771', '9937', 's', 'v', '3181', '5381', '4137', 'm', 'y', '3759', '599', 'x', '7683', 'j', 't', '2275', '6389', '4321', '5085', 'b', '3029', '5621', '2167', '5671', 'j', 'm']
[EX A]:
b, i, j, m, n, s, t, u, v, x, y