You will be given a definition of a task first, then some input of the task.
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.

['y', '5287', '9523', '8211', '2569', 'c', 'y', 'g', 'r', 'k', '7341', '8631', 'p', 'y', '9497', 'i', 'c', 'x', '6671', '9071', 'w', '697', '5009', '8127', 'j', '6737', '797', 'b', '5087', 'y', 'n', 'f', '8585', 'h', 'g', 'x', 'g', 'z', '8781', '8243', 'y', 'd']
Output:
b, c, d, f, g, h, i, j, k, n, p, r, w, x, y, z