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.

['3511', 'i', 'z', 'x', '1761', '5977', '3111', 'b', '8255', 'a', 'g', 'y', '5987', 'q', 'n', 'y', 'j', 'k', 'w', 'a', '2249', '4719', '7533', '7455', 'y', 'q', 'o', '5947', 'l', '2543', 'f', '3867', 'y', 'y', 'l', '1725', '6257', 'k', '4387', 'd', '3149', '3871', 'z']
Output:
a, b, d, f, g, i, j, k, l, n, o, q, w, x, y, z