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.

Let me give you an example: ['8129', 'a', '4245', 'y', 'm', 'a']
The answer to this example can be: a, m, y
Here is why: Here, the unique alphabets in the list are 'a', 'y', and 'm', hence their sorted order is 'a, m, y'.

OK. solve this:
['h', '2681', 'h', 'p', 'p', '1897', 'o', 'b', 'e', '5927', 'x', 'n', 'v', 'o', 'r', 's', '8587', 'm', '9025', 'x', '8203', '5855', '9075', '7023', 'l', '5679', '8421', 'c', 'a', '2785', 'k', 'm']
Answer:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
a, b, c, e, h, k, l, m, n, o, p, r, s, v, x