TASK 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.
PROBLEM: ['5489', 'f', '6833', 's', 'c', '6575', 'w', '2957', '8465', 'v', 'h', '2119', '7731', 'e', '5367', 'e', '3357', 'p', '7565', 'n', 'x', 'n', 'f', '1075', '5941', '6505', 'j', 'p', '2853', 'l', 'q', '4727', 's']

SOLUTION: c, e, f, h, j, l, n, p, q, s, v, w, x

PROBLEM: ['3019', 'g', 'q', 'u', '611', 'z', '3671', '8119', '1679', 'h', '2631', '655', 'k', '2837', 'e', 'f', 'e', 'f']

SOLUTION: e, f, g, h, k, q, u, z

PROBLEM: ['8711', '2931', 'u', 'j', '8843', '6971', '2695', '7605', 'q', 'x', 'u', 't', 'f', 'd', 'r', 't', '107', 'n', 'g', '6921', '6299', '9883', '2017', 'x', '9465', 'x', '5545', 'q', 'z', 'p', '5013', '7451', 't', '8595', 'g', 'n', '8429', 'e', '8449', 'v', 'w']

SOLUTION:
d, e, f, g, j, n, p, q, r, t, u, v, w, x, z