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: ['7595', '5303', '3985', 'n', 'w', 's', 'r', 'f', '8237', 'q', 'y', 'f', '3121', '2463', '4597', 'q', '6801', 'f', 'i', '8563', '3267', 'k', '6157', 'f']

SOLUTION: f, i, k, n, q, r, s, w, y

PROBLEM: ['1121', 'j', '1433', 'g', 'l', '1479', '1699', 'j', 'a', '8507', 'd', 'a', '5229', 'k', 'x', '4549', 'e', 'p', '1367', 'u', 'd', '785', '215', 'e', 'f', 'a', '101', '7575', '7965', 'p', 'i', '5637', '1005', 'i', 'y', '181', 'r']

SOLUTION: a, d, e, f, g, i, j, k, l, p, r, u, x, y

PROBLEM: ['o', 'u', '4227', '3699', '7397', '4519', '8089', '6609', 'q', 'e', 'd', '2385']

SOLUTION:
d, e, o, q, u