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: ['1345', 'y', '7221', 'h', 'r', '3255', 'k', 'r', 'j', '8639', '467', 'f', 'k', 'n', 'k', 'j', 'l', 'w', '143', 'w', 'q', '5657', '589']

SOLUTION: f, h, j, k, l, n, q, r, w, y

PROBLEM: ['6209', 'x', 'j', 'w', '7965', '4905', '6297', '4291', '7183', 'a', 'l', '5267', 'r', '5935', 'a', '7865', 'h', 'p', '6117', 'a', 'y', 'y', 't', 'v', '7271', 'e', 'e', 'z', 'i', 'l', '4731', '2059', 'm', '5703', 'k', 'f', '8125', 'e', '7569', 'r', '2287', '593']

SOLUTION: a, e, f, h, i, j, k, l, m, p, r, t, v, w, x, y, z

PROBLEM: ['j', '2097', '8539', '3599', 'o', 'i', 'j', '5959', 'q', '7623', '4853', '6017', 'g', '861', '1589', '4837', '4937', '6441', '8253', 'i', 'u', '885', '3831', 'j', 'r', '5905', 'g', '6933', 'e', '2429', '6807', '4721', 'd', 's', 'i', '5191']

SOLUTION:
d, e, g, i, j, o, q, r, s, u