Detailed 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.
Q: ['i', '2417', '1395', '8569', '5613', '8969', '2559', '5301', '7251', '7599', '377', 'w', '9323', '7497', '9489', 'a', '9353', '5781', '4651', '3743', 'k']
A:
a, i, k, w