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]: ['r', 'n', '7583', '8697', '7927', 'l', '5003', '1363', 'p', 'e', 'q', '6227', '6915', '8619', '9011', 'n', '3063', '3799']
[EX A]: e, l, n, p, q, r

[EX Q]: ['7055', '2573', '1713', 'x', 'm']
[EX A]: m, x

[EX Q]: ['q', '987', '643', 's']
[EX A]:
q, s