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.

[Q]: ['9579', 'm', 'v', 'r']
[A]: m, r, v


[Q]: ['8879', 'x', '1383', '4925', '2867', 'j', 't', 'e', 'w', 'p', 't', 'w', 'l', '7447', '1877', '7747', 'k', 'b', 'x', '8565', 'q', '8575', '5711', '2949', '5637', '2197', '4905']
[A]: b, e, j, k, l, p, q, t, w, x


[Q]: ['4591', 'y', 'y', '8799', 'n', '2191', 'g', 'l', 'o', '5085', '4773', '2265', 'j', '8661', '3497', 'p', '127', 'y', '4445', '8979', 'y', 'd', 'y', 'b', 'x', '3543', 'j', '5809', '6071', '5519', '7819', '1745', '9419', 'l', '2179', '4353', 'v', 'v', '8409', '3585', 'a', '6577']
[A]:
a, b, d, g, j, l, n, o, p, v, x, y