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.

['6249', '1235']
-1

['k', '6595', '1595', 'v', 'h', 'b', '8815', '6681', 'j', '7581', 'p', '9095', '5453', 'r', 'y', '7755', 'x', '1853', 'k', 'q', 'u', 'j', 'q', '9651', 'o']
b, h, j, k, o, p, q, r, u, v, x, y

['7815', '8923', '6329', '7375', '1359', '1405', '4207', '3077', '6725', 'm', 't', '9277', '3183', '1657', 'd', 'u', '3107', 'a', '2577']

a, d, m, t, u