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: ['h', '9675', '2329', 'l', '7553', '8133', 'p', 'm', 's', 'b', '5279', '1311', 'g', '5735', 'm', '2967']
A:
b, g, h, l, m, p, s