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.

[EX Q]: ['t', 'x', '1699', '8727']
[EX A]: t, x

[EX Q]: ['1233', '405', '8901', '7147', '8841', 's', 'v', '3131', 'p', 'd', 'y', '5873', '439']
[EX A]: d, p, s, v, y

[EX Q]: ['1007', 'd', '5287', '9417', '3687', '1969', '4841', 'b', 'b', 'f', 'x', '1969', 'w', 'e', '9859', '8377', '4349', '7545', '3769', '6747', '6113']
[EX A]:
b, d, e, f, w, x