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: ['231', 'r', '5673', 'j', '589', 'z', '4659', 'a', '3763']

SOLUTION: a, j, r, z

PROBLEM: ['l', '7111', 'd', 'e', 'h', 'z', 'x', '5673', 'v', '8255', 'i', 'z', 'c', 'i', '4287', 'q', '9293', '9137', 'p', 'n', 'o', 'n', '7883', '6453', '7355', '8769', 'y', '9153']

SOLUTION: c, d, e, h, i, l, n, o, p, q, v, x, y, z

PROBLEM: ['g', 'b', '9529', '8507', 'g', '6351', '1795', '515']

SOLUTION:
b, g