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: ['1971', 'g', 't', 't', 'x', 'q', 'o', 'm', 'h', '9481', '1729', '5527', 'u', '3157', 's', '8795', 'z', 'g', 'i', '1649', 'p', '65', 's', 'u', '6843', 'r', 'l', 'k', 'n', 's', 'm', '7991', 'u', 'a']
Example Output: a, g, h, i, k, l, m, n, o, p, q, r, s, t, u, x, z

Example Input: ['z', '2519', '4799', '4715', '7165', 'r', 'r', 'l', 'n', '6925', '8935', '9795', '5489', 'v', 'u', '6527', '2241', 'u', 'c', 'w', '9755', 'w', '9823', 'g']
Example Output: c, g, l, n, r, u, v, w, z

Example Input: ['7327', '3421']
Example Output:
-1