Given the task definition, example input & output, solve the new input case.
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.
Example: ['8129', 'a', '4245', 'y', 'm', 'a']
Output: a, m, y
Here, the unique alphabets in the list are 'a', 'y', and 'm', hence their sorted order is 'a, m, y'.

New input case for you: ['5039', 'n', '8931', 'k', '1889', 't', 'v']
Output:
k, n, t, v