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: ['w', 'e', '291', '1507', '9577', 't', '5459', 't', '207', '2853', '3629', '5951', '7279', 'n', 'c', '6909', 'x', 'd', 'j', 'u', '4315', '1641', 's', '8411', '7685', '229', 's', '9973', '3659', 'i', 'f', '3167', '2125', '6167', '3243', 'a', 'k', 'g', '8453', 'j', 'y', '4257']
Output:
a, c, d, e, f, g, i, j, k, n, s, t, u, w, x, y