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]: ['4009', 'y', '9077', 'p', 'q', '6711', '6443', '5491']
[EX A]: p, q, y

[EX Q]: ['6597', '7889', 'x', 'v', 'm', 'j', 'j', 'w', 'v', '177', 'x', '8353', '5897']
[EX A]: j, m, v, w, x

[EX Q]: ['8523', '8463', 't', '9149', '1071', '5361', '99', 'f', '9517', '5437', 'q', '1035', 'a', 'u', '6467', '1219', '9405', 'o']
[EX A]:
a, f, o, q, t, u