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: ['j', '1733', 'p', '6741', '7933', '8943', '733', 'x', '1107', 'z', '1719', '7653', 'y', 'z', '6563', 'p', '4615', 'j', '4489', 'h', 'w', 'y', 'p', 'c', '7949', 'k', 'm', 'r', '9427', '7243', '9777', 'j', '323', '4095', 't']

SOLUTION: c, h, j, k, m, p, r, t, w, x, y, z

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: ['b', '1415', '4659', 'x', '2637', 'g', '883', '1173', 'x', '6619', '7197', 'e', 'g', 'g', 'z', 'b', 'j', '8101', '3295', '7521', '8659', '2083', '1579', '3737', 'x', 's', 'w', '2073', 'a', 'x', 'x', '4599', '7855', 'h', '6467', '8923', '2881', '5837', '2619', '2171', '1443', '7655', 'v', 'f']

SOLUTION:
a, b, e, f, g, h, j, s, v, w, x, z