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: ['8235', 't', '1695', '9899', '3633', 't', '1823', 'r', 'x']

SOLUTION: r, t, x

PROBLEM: ['r', '9489', 'e', 'n', '6323', 'd', '3163', '265', '8587', '7891']

SOLUTION: d, e, n, r

PROBLEM: ['s', 't', '7935', '691', 'd', 'z', '3277', 'i', 'q', '7669', 'b', '4973', 'h', '4853', '2687', 's', 'q', '9311', 'q']

SOLUTION:
b, d, h, i, q, s, t, z

