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: ['9113', '3625', 'u', '8189', '3649', '259', '5539', '1583', 'g', '4037', 'y', 'v', '8337', 'd', 'q', 'j', 'c', 'h', 'p', '1601', 'z', 'c', 'n', '1767', '1679', '1805', 'm', '4469', '2487', '6015', '973']

SOLUTION: c, d, g, h, j, m, n, p, q, u, v, y, z

PROBLEM: ['h', 'v', '1263', 'y', '3299', 'd', 'a', 'h', 's', '2007', '7597', '1015', 'k', '6643', '6959', 'g', 'u', 'd', '5737', 'n', 'z', 'y', 'b', 'g', '9059', '7349', 'j', 'w', 'i', 'z', 'p', '5809', 'x', '4421', 'g', '6399', '3965']

SOLUTION: a, b, d, g, h, i, j, k, n, p, s, u, v, w, x, y, z

PROBLEM: ['2233', 'j', 'e', '9327', '6673', '6675', 'p', '1211', '2463', '4239', '3709', 'm', 'j', '8437', 'l', 'd', 'm', 'b', '8539', '2403', 'p', 'p', 'x', '8405', '3481', '1015']

SOLUTION:
b, d, e, j, l, m, p, x