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: ['8859', '575', 'l', 'e', '6575', '1303', '8643', '1395', '3171']

SOLUTION: e, l

PROBLEM: ['a', '3281', '9123', '5443', 'w', 'w', 'p', '9275', 'v', 'm', '3549', 'l', 'y', 'l']

SOLUTION: a, l, m, p, v, w, y

PROBLEM: ['1817', 'b', '3473', '5215', '2533', 'k', '7029', 'h', 'g', '5845']

SOLUTION:
b, g, h, k