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]: ['a', 'p', 'y', 'l', 'l']
[A]: a, l, p, y


[Q]: ['s', '9241', 'j', 'o', 't', '9687', '8441', 'r', '7901', '7165', 'm', 'f', 's', '1877', 'n', '8301', 'l', '9583', '7857', 'm', 'q', '3153', '3743', 'm', 'v', 't', '7845', 'g', 't', 'k', 'c', 'a', '6873', 'a', '4833', 's', '3227', 'n', '4717', '6821']
[A]:
a, c, f, g, j, k, l, m, n, o, q, r, s, t, v