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: ['1749', 'i', 'w', 'j', '3171', '1999', '1037', '4937', '7013', '3593', '287', 'o', 'i', 'j']

SOLUTION: i, j, o, w

PROBLEM: ['8281', '4831', '1329', 'g', 'e', '8879', 'n', 's', 'x', 'j', '6305', 'j', '921', '3677', '5107', 'n', 'j', '9285', 'a', '5329', '6671', 'c', '9283', 'l', 'a', '7907', 'q', '7605', '855', '6477']

SOLUTION: a, c, e, g, j, l, n, q, s, x

PROBLEM: ['z', 'j', 't', '2161', 't', '7569', '6713', 't', '6543', 'v', '4291', '9025', 'z', 'm', 'v', '9965', 'p', 'z', '5301', 'r', 'g', 'r', 'p', 'q', '4061']

SOLUTION:
g, j, m, p, q, r, t, v, z