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: ['1653', '3177', 'b', '2785', '2515', 'd', '5513', '5599', '2947', 'v', '2771', '5697', '2913', '4161', '5939', '2655', '6787', '9851', 'q', '3199', 'x', '1305', '9423', '9117', '4821', 'j', '7963', 'i', 's', '469', 'r', 'w']

SOLUTION: b, d, i, j, q, r, s, v, w, x

PROBLEM: ['m', '5005', 'y', 'h', 'w', '3609', 'p', '2539', '3307', 'p']

SOLUTION: h, m, p, w, y

PROBLEM: ['9381', '4833', '2185', 's', 'r', 's', '6385', '2271', '8183', 'q', '5441', 'z', 'e', '4429', 'p', 'g', '5485', 'k', '7125', '573', '5519', '4125', '7703', 'k', 'x', '3077', 'y', 't', 'e', '195', 't']

SOLUTION:
e, g, k, p, q, r, s, t, x, y, z