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: ['8975', '7199']

SOLUTION: -1

PROBLEM: ['4041', 'l', 'g', '9571', '9295', '1395', 'l', 'p', 'f', 'w', 'g', '1721', '2421', 'w', 'z', '2235', 'p', '7851']

SOLUTION: f, g, l, p, w, z

PROBLEM: ['q', '8209', '25', 'i', '6411', 'g', '1895', 'g', '3235', '5707', 'h', '6827', 'q']

SOLUTION:
g, h, i, q