Definition: 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: ['7819', '4605', 'v', '5039', 'd', 's', 'd', '5143', '4021', '2977', 'g', '8425', '159', '5561', 'u', '3857', '2925', '3329', '7091', 'k', '9135', '121', 'z', '8769', 't', '4423', '2699', 'm', 't', 'd', '2803']
Output:
d, g, k, m, s, t, u, v, z