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: ['y', 'p', 'q', '2157', 'b', 'w', '8875', 'k', 'i', 'd', '9743', '4941', 'b', 'p', '9941', '495', 'h', 'i', '839', 'c', 'h', 'f', 'b', 'a', 'k', 'z', '7549', '4149', 'h', 'j', '1947', 't', 'f', 'c', '1243']

SOLUTION: a, b, c, d, f, h, i, j, k, p, q, t, w, y, z

PROBLEM: ['1197', '305', 's', '1113', 'n', '2207', 'e', '227', '2833', '607', '3049', 'v', '4615', 'a', 'k', 'r', 's', '3571', 'f', '4215', 'f', '8985', '5559', '4111', 'u', '1433', '1943', '8831', 'w', 'x', 'o', '9023', 'u', 'y', 'p', 's', 'h', '8877', 'p', 'n', '8903', '5811']

SOLUTION: a, e, f, h, k, n, o, p, r, s, u, v, w, x, y

PROBLEM: ['4437', '9625', '2445', '4025', 'w', 'e', '6775', '4317', '1621', '6199', '1151', 'b', '2159', 'j', 'j', '9757', '2621', 'f', '9929', '5533', '3405', '9915', 'm']

SOLUTION:
b, e, f, j, m, w