Instructions: 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.
Input: ['8949', 'o', '8133', 'v', '6387', '5505', '8097', '9385', '4643', 'a', '9645', '4665', 't', 'y', 'q', '4715', '6581', '9067', '7699', '9091', '5125', 'n']
Output:
a, n, o, q, t, v, y