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: ['2697', 's', '8733', 'n', '5871', 'f']

A: f, n, s
****
Q: ['q', 'g', 's', 'g', 'z', '987', '777']

A: g, q, s, z
****
Q: ['q', '2233', '4605', 'l', '1989', '7159', '7935', '8003', 's', 'c', 'q', 'b', 'r', 'n', '4173', 'i', '3167', 'h', '4217', '3237', 'p', 'p', 'w', '5399', '2875', 'q', '5893', '5183', 'm', '1759', '2985', '5979']

A:
b, c, h, i, l, m, n, p, q, r, s, w
****