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: ['8495', 'p', 'j', 'm', 'n', '9115', '1183', 'r', 'r', '8735', 'a', 'i', 'k', 'p', '8927', 'r', '9283', '9563', 'g', '2503', 'h', '1091', '5257', 'a', '3061', '2835', 'l', 'w', 'j', '7617', '8793', '7463', 'h', '8467', '7337', 'b', '4655', 'd']

SOLUTION: a, b, d, g, h, i, j, k, l, m, n, p, r, w

PROBLEM: ['r', 'j', '437', 'b', '5223', 'n', 'v', '437', 'd', '8285', 'k', 'j', 'r', 'p', 'n', 'e', 'n', 'j', 'o', '2651', 'j', '6365', 'q', 'q', '2159', 'g', '3641', '7727', 'c', '1197', 's', 't', 'n']

SOLUTION: b, c, d, e, g, j, k, n, o, p, q, r, s, t, v

PROBLEM: ['d', '9779', '5807', '595', '635', '1531', 'e', 'w', 'b', '2037', 'm', 'i', 'y', '1489', 'j', 'e', '7447', 'x', '1915', '8643', 'e', '2665', 'y', '6575', '4411', '3439', 'd', '5735']

SOLUTION:
b, d, e, i, j, m, w, x, y