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: ['t', 'm', '7071', 'j', '353', 'n', 'a', 'm', '9211', 'i', '9537', 'q', '7669', '869', '8753', '8071', '375', '9971', 'c', 'n', '5851', 'u', '2491', '2697', '2789', '4683', '879', 'q', 'g', 'p', 'd', 'x', 'r', 'i', '8171', '5449', '2477', '1151', 'z', '3845', '1079', 'j', 'n', 'p', '8199']
Example Output: a, c, d, g, i, j, m, n, p, q, r, t, u, x, z

Example Input: ['u', 'd', '4193', '5687', 'p', 'r', '7787', 't']
Example Output: d, p, r, t, u

Example Input: ['6903', '565', '1975', 'u', 'z', 'i']
Example Output:
i, u, z