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: ['1233', '405', '8901', '7147', '8841', 's', 'v', '3131', 'p', 'd', 'y', '5873', '439']

SOLUTION: d, p, s, v, y

PROBLEM: ['5463', '5683', 'w', '4071', '3997', 'i', '9677', 'q', 'l', 'v', 'w', '5325', '197', 'g', 'g', '3227', '3477']

SOLUTION: g, i, l, q, v, w

PROBLEM: ['k', '227', '9601', 'f', 's', 'g', 'v', '105', '4847', '7417', 'm', 's', '1489', '4957', 'j', 'o', 'c', 'p', '5013', 'r', '327', 'h', 'h', '7025', '3419', '853', '687', '5807', '4825', '4939', '1331', 'v', '6769', 'j', 'b', '4831', 'v', '2327', 'j', 'l', 'n', '4309', 'h', '4291', '6847']

SOLUTION:
b, c, f, g, h, j, k, l, m, n, o, p, r, s, v