Definition: 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: ['2181', '7019', 'l', 'z', 'z', 'y', '1245', '4179', '6951', '7249', '2723']

l, y, z