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.

[Q]: ['1449', 'a', '6261', '303', '4651', 'n', 'u', '1595']
[A]: a, n, u


[Q]: ['s', '2507', '3091', 'g', '7643', '2573', 'w', 'r', '1977', 'q', 'c', 'j', '1335', '9671', '7317', '567', '2041', '5777', 'w', 'm']
[A]: c, g, j, m, q, r, s, w


[Q]: ['2393', 'h', '863']
[A]:
h