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]: ['6737', 'g', '9985', '5257', 'k', 't', '7863', 'y', '8319', 'l', 'o', '6505', '6531', 'z', '3055', '2943', '3625', 'h', '4867']
[A]: g, h, k, l, o, t, y, z


[Q]: ['f', '3409', 'i', '4147', '1745', '6007', 'l', 'd', 'i']
[A]: d, f, i, l


[Q]: ['7291', '5289', 's', '8635', '6101', 'x', 'r', 'x', '5457', '1005', '6569', '5857', 'v', 'x', 't', 's', '6883', '3119', '1095', 't', 'o', '5281', 'v', 'n', 'k', 'r', 'b', 'y', '6191', '505', 'w', '7899', '3535', '7677', 't', '5489', '1175']
[A]:
b, k, n, o, r, s, t, v, w, x, y