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: ['1429', '7763', '9737', 'l', '1865', 's', '9871', 'e', 'c', 'q', '2727', 'v', 'p', 'd', 'p', '6771', 'c', '7051', 'e', 'b', 'd', 'o', '7427', 'x', 'e', 'm', 'u', '4887', '1649', 'u', 'h', '5249', 'e', '7579', '8549']

SOLUTION: b, c, d, e, h, l, m, o, p, q, s, u, v, x

PROBLEM: ['5075', '9169', '4659', '7605']

SOLUTION: -1

PROBLEM: ['4411', 'q', '6425', '6519', 'n', '3443', 'o', 'b', 'j', '9341', '645', '9533', '4059']

SOLUTION:
b, j, n, o, q