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: ['o', 'c', '6469', 'x', '8815', '4441', '6193', 'u', 'm', 'a', '9879', 'p', '8335', 'c', 'z']

Output: a, c, m, o, p, u, x, z


Input: Consider Input: ['9539', '4653', '8299', '9617', 'x', '2529', '797', 'b', '1853', 'q', 'k', 'e']


Output: b, e, k, q, x