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: ['1063', 'f', 'm', 'i', 'x', 'i', 'd']

SOLUTION: d, f, i, m, x

PROBLEM: ['a', '7599', 'i', '9455', '3955', '2015', 'j', '7345', 'x', 't', 'c', '1317', '9155', '6383', '7793', 'n', '5581', 'v', '3485', 'n', 'r']

SOLUTION: a, c, i, j, n, r, t, v, x

PROBLEM: ['9165', '8229', '5063', 'r', '55', 'z', '5049', '7159', '3543', '1345', '3407', 'j', 'x', 'v', 'u', 'u', 'i', '871', 'z', 'y', 'k', 'z', '5671', '5993', 's', 's', 'q', '1127', 'w']

SOLUTION:
i, j, k, q, r, s, u, v, w, x, y, z