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]: ['2165', 'f', '5081', 's']
[EX A]: f, s

[EX Q]: ['9013', 'e', 'm', 'p', 'k', '161', 'k']
[EX A]: e, k, m, p

[EX Q]: ['t', 'e', '7061', 'y', 'c', '7647', '9421', 'z', '3531', 'm', '3741', '2823', 'w', '197', '8007', 'b', 'n', 'e', '2137', '349', 'z', '3065', '4763', '9693', 's', 'b', '3135']
[EX A]:
b, c, e, m, n, s, t, w, y, z