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.

Example Input: ['k', 'v', 'e', '6377', 'y', '3585', '4535', 'f', 'g', 'm', 'f', '8369', 'v', '7445', '4527', '9383', 'n']
Example Output: e, f, g, k, m, n, v, y

Example Input: ['a', 'a', 'b']
Example Output: a, b

Example Input: ['b', 'r', 'y', 'a', '4929', '419']
Example Output:
a, b, r, y