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]: ['3035', 'f', 'k', 'e', '3023', 'p', '9667', '5277', '4757', '8433', 'g', '1399', '7721', 'n', 'p', '7469', '7581', '5679', 'g', 'q']
[EX A]: e, f, g, k, n, p, q

[EX Q]: ['6249', '1235']
[EX A]: -1

[EX Q]: ['9015', '1799', 'z', '2163', '4959', '4821', '987', 'r']
[EX A]:
r, z