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: ['6769', '1057', '1021', 'n', '8231', '9173', '8123', 'a', '6053', 'q', 'y', '883', 'r', '1215', 'x', 'o', '9531']

Output: a, n, o, q, r, x, y


Input: Consider Input: ['7109', '1243', 'f', 'z', 'h', 'd', '6169', 'v', 'h', '3609', '3181', 'd', '3661', '7193', '7341', '9127', 'r', '1623', '5813', 's', 'd', '4011', '4983', 'n', '4195']

Output: d, f, h, n, r, s, v, z


Input: Consider Input: ['5411', '7665', 't']


Output: t