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.

['2333', 's', '2915', '7249', '3533', '1475', '2791', '8019', 'h', 'j', '6393', 'c', '191', 'a', 'x', 'z', 'q', '5115', '6763', '6787', '9911', '9015']
Output:
a, c, h, j, q, s, x, z