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: ['k', '6595', '1595', 'v', 'h', 'b', '8815', '6681', 'j', '7581', 'p', '9095', '5453', 'r', 'y', '7755', 'x', '1853', 'k', 'q', 'u', 'j', 'q', '9651', 'o']

SOLUTION: b, h, j, k, o, p, q, r, u, v, x, y

PROBLEM: ['331', '125', 'u', 'a', 's', '6995', 'i', '3613', '9727', '7087', 'l', 'b', '8291', '813', 'i', '1169', '2159', 'd', '1451', 'q']

SOLUTION: a, b, d, i, l, q, s, u

PROBLEM: ['p', 'v', 'e', 'f', '2515', 'w', '8831', '5233', 'u', 'f', 'y', 'l', 'l', 'r', 'l', '4237', 'e', '2565', '8081', 'v', '7337', 'q', '5031', 'f', '3679', 'g', '8085', 'e', 'i', 'v', '3999', 'w', 't', '3583', 's', '2989', 'l', 'k', '4833']

SOLUTION:
e, f, g, i, k, l, p, q, r, s, t, u, v, w, y