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: ['z', '5601', '5675', 'w', 's', 'z', '9213', '9563', '1699', 'p', 'g', 'm', 'c', '9279', '4481', 'p', 'n', '2389', 'c', '503', '1901', '8827', '1701', '1607', '5633', 'a', 'z', 'g', '3175', 's', 'l', 'l', '6811', '1821', '693', '8277', 'q', '8623', 'o']
Example Output: a, c, g, l, m, n, o, p, q, s, w, z

Example Input: ['e', '2797', '7163', 'i', 'i', 'p', '8983', '4749', 'f', 'e', 'u', 'y', '4491', '5739', '6729', '499', '8701', '1487', '2113', '699', '6461', 'h', 'v', 'm', '9979', 'q', '623', 'h', '6857', 'b', '8649', '2143', 'f', 'i', '1139', '4525', '795', '1843', 'g', 'n', '5509', 'i']
Example Output:
b, e, f, g, h, i, m, n, p, q, u, v, y