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.

Example Input: ['7997', 'm']
Example Output: m

Example Input: ['v', '2989', 'z', '7843', 'e', '9923', 'y', 'b', '7611', 'u', 'u', '6227', '3145', 'w', '6451', 'g', '3129', 'o', 'r', 'z', '8349', 'u', 'h', 'd', 'g', 'a']
Example Output: a, b, d, e, g, h, o, r, u, v, w, y, z

Example Input: ['o', 'g', '1777', 'o', 'j', '2377', '6313', 'o', '9673', 'p', '6857', 'j', 'z', '4507', '5425', 'l', 'l', 'o', 'y', '4505', 'n', 'q', '9553', 'c', '9177', 'b', 'b', '8563', '7131', 'w', 'l', 'c', '2643', 'c', 'g']
Example Output:
b, c, g, j, l, n, o, p, q, w, y, z