Instructions: 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: ['q', '2057', 'e', '3481', 'c', '567', '237', '2911', '3597', '9263', '529', '5743', 'y', '1549', '4915', '4795', 'f', 'r', '5773', 'a', 'l', '5911', 'x', '1705', 'f', '2517', '4669', '3617', 'p', 'g', 'n']
Output:
a, c, e, f, g, l, n, p, q, r, x, y