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: ['6463', '871', '5781', '283', '9653', 'f', '9661', '3365', '2889', '5499']

SOLUTION: f

PROBLEM: ['1595', '2915', 'o', 't', 'c', 'h', '3969', '5407']

SOLUTION: c, h, o, t

PROBLEM: ['o', '9461', 'j', 'p', 'c', 'j']

SOLUTION:
c, j, o, p

