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: ['q', 'o', '1205', '4429', '6301', 'e', '2857', '5075', '5121', 'p', 'b', '5801', 'a', 'm', 'j', 'p', '1279', '7011', 'x', '2557', 'k', 'v', 'b', 'u', 'w', 'n', '1689', 'o', '1583', 'w', '6403', 'p', '6397', 'e', '823', '5699', 'd', '3399', 'd', 'b']

SOLUTION: a, b, d, e, j, k, m, n, o, p, q, u, v, w, x

PROBLEM: ['u', '1343', 'd', 'c', '9567', 'e', 'd', 'y', 's', '4199', '3217', '2937', '9345', 'd', 'l', '9875', '5987', 'p', '2585', '5843', '9643', '2423', 'e', 'l', 's', '3503', 'b', 'w', '9685', 'p', '6055', 'k', 'e', 'e', 't', '865', '6071', 'j', '3439', 't']

SOLUTION: b, c, d, e, j, k, l, p, s, t, u, w, y

PROBLEM: ['t', 'c', '5083', '8493', '1247', '6329', 'e', '4083', 'p', 'z', 'l', 'l', 'a', '8911', 'y']

SOLUTION:
a, c, e, l, p, t, y, z