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]: ['k', 'n']
[EX A]: k, n

[EX Q]: ['a', '2579', 'f', '6787', '123', '225', '6499', '4419', 'o', '1785', '7981', 'z', 'b', '2441', '2821', 'o', 'k', '2747', 's', 'u', 'q', '3901', '7629', 'k', 'm', 'q', '6577']
[EX A]: a, b, f, k, m, o, q, s, u, z

[EX Q]: ['8775', '2159', 'k', 'h']
[EX A]:
h, k