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.

['i', 's']
i, s

['4269', '1847', '2025', '601', 'g', 'n', 'h', '3499', '4977', '3579', '9355', '3489', 'm', 'm', '4401', '4605', 'l', '3977', 'h', 'd', 't', '5135', '7787', 'k', 'q', '7699', '5325', '6269', '1865', 'h', '8915', '5677', 'g', '603', '1435']
d, g, h, k, l, m, n, q, t

['8707', 'o', 'g', 'y', 'k', '2003', 'z', 's', '487', 'i', 'b', 'r', 'l', '9727', 'v', '8045']

b, g, i, k, l, o, r, s, v, y, z