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: ['c', '4881', '6893', '3729', 'j', '2385', 'q', 'v']

SOLUTION: c, j, q, v

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: ['r', 'g', '1909', '7881', '6325', '6111', 'v', '2245', 'i', 'v', 'g', '2057', '4807', 'h', 'l', 'p', '9267', 'v', '4345', '7597', 'e', '8195', 'x', 'b', 'j', '3737', 'a', 'r', '4755', 'h', '8157', '1135', 'j', 'c', 'm', '3923']

SOLUTION:
a, b, c, e, g, h, i, j, l, m, p, r, v, x