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: ['4993', 'n', '7115', 'f', 'd', 'q', '249', '3203', 'w', '5689', '4103', '7129', '603', 'e', 'z', '5571', '3241', '6029', '2721', '8451', 'o', '7841', 'p', '6271', 'r', 'b', '9481', '4045', 'v']
Example Output: b, d, e, f, n, o, p, q, r, v, w, z

Example Input: ['w', 'r', '171', 't', 'a', 'b', '3945', 'k', '6653', 'r', 'd', '8107', '5087', '167', '7469', '7479', '9563', '4611', 'v', 'k', '5433', 'e', 'z', '3653', '5123', '3179', '4987', 'h', 'z', '8271', 'z', 'u', '861', 'k', '3989', '7917']
Example Output:
a, b, d, e, h, k, r, t, u, v, w, z