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.

['p', '2923', 'e', 'k', '5433', '605', '5079', 'k', 'p', 'x', '4845', '4099', '6795']
e, k, p, x

['4213', '3595', '7937', 'y', '5723', 'v', 'b', '7007']
b, v, y

['6867', '9697', '2677', '6385', 'h', 'q', 'h', 'w', 'e', '9431', '1783', 'v', 'c', '4463', '1025', '2919', '7083', '2061', 'j', 'k', 'v', '1231', '1697']

c, e, h, j, k, q, v, w