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.

Input: Consider Input: ['s', '2507', '3091', 'g', '7643', '2573', 'w', 'r', '1977', 'q', 'c', 'j', '1335', '9671', '7317', '567', '2041', '5777', 'w', 'm']

Output: c, g, j, m, q, r, s, w


Input: Consider Input: ['s', 's', '3619', '6051', 'h', '213', '3937', 'v', 'p', 'y', '8449', '9337', '5327', 'a', 'a', 'w', '3985', 'n', 'm']

Output: a, h, m, n, p, s, v, w, y


Input: Consider Input: ['9151', '3223', '5201', '8533', '1055', 'f', '9121', '9427', 's', '7839', 'k', '6673', 'i', '9597', '9551', 'b', '9585', '1457', 's', '4301', 'r', '7825', 'o', '6181', '6777']


Output: b, f, i, k, o, r, s