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: ['e', 'q', '4405', 'd', 'c', 'k', 'j', '4893', '7999', '8939', 'k', 'r', 'l', '7349', 's', '7877', 'v', 'n', 'c', '8015', '2989', '623', 'n', '983', '3567', 'y', '2503', '3519', '7987', '2519', 'y', 'a', 'd', '3981', 'x', 'r', 'o', '9937', 'z']
Output:
a, c, d, e, j, k, l, n, o, q, r, s, v, x, y, z