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: ['p', '3981', 'e', '5949', 'p', '4075', '1919', 'w', 'r', '8059', '4303', 'f', '5201', '2255', '2737', '7395', '8809', 'j', 'z', 'n', '4797']

SOLUTION: e, f, j, n, p, r, w, z

PROBLEM: ['r', '9489', 'e', 'n', '6323', 'd', '3163', '265', '8587', '7891']

SOLUTION: d, e, n, r

PROBLEM: ['7155', 'b', 'o', 'd', '7543', '4707', 'y', 'd', '9883', '5675', '4225', '4489', '6755', 'o', '135', 'i', 'x', 'e', '1867', '9353', '6937', 'h', '7651', 'f', 'i', 'w', '5199', '3317', 's']

SOLUTION:
b, d, e, f, h, i, o, s, w, x, y

