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: ['4641', '2881', 'c', '4827']

SOLUTION: c

PROBLEM: ['j', 'r', 'z', 'f', '1485', '2419', 't', 'd', '6023']

SOLUTION: d, f, j, r, t, z

PROBLEM: ['z', 't', '9371', 'b', 't', '8551', '3133', 'l', '4367', 'c', 'l', '407', '7485', '3011', 'y', '2045']

SOLUTION:
b, c, l, t, y, z

