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: ['1799', '6409', '9257', '5923', 'm', 'j', '2565', '715']

SOLUTION: j, m

PROBLEM: ['6813', '7183', 'j', '4115', '3915', '3605', '7853', 'p']

SOLUTION:
j, p