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: ['9483', '501', 'j', 'k', '3103']

SOLUTION: j, k

PROBLEM: ['2741', '2541', '8943', 'l', '4047', '2211', 'p', 'e', 't', '7645', '9771', 'f', '5063', '2303', '6097', '5089', 'd', 'e', '1409', '3125', '2171', 'g', '1247', '4045', 'v', 'h', 'u', '2587', '5207', '5553', 'g', 'd', '6891', 'e', '2471', '2435']

SOLUTION: d, e, f, g, h, l, p, t, u, v

PROBLEM: ['x', '7455', '8967', '829', 'b', '5027', 'u', 'h', 'q', 's', '3133', 'a', 'u', '1379', '1297', '1019', '3295', 'd', '901', '1361', '7211', 'v', '5187', '1991', 's', '8553']

SOLUTION:
a, b, d, h, q, s, u, v, x