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: ['g', '6867', '7965', '3313', 'k', '1827', '7337', 'u', '1209', '5145', 'w', 'h', '9059', 'u', 'b', '3189', '2837', 'k', 'y', 'e', 'b', '4479', '541', '7103', 'h', 'm', '2177', '6377', '3993', '7167', 'q', '2145', '5007', '9135', '5331', 'e']

SOLUTION: b, e, g, h, k, m, q, u, w, y

PROBLEM: ['9947', '3353', '8643', '4621', '4857', 'y', '7075', 'c', '8911']

SOLUTION: c, y

PROBLEM: ['6515', '2757', '955', 'r', '8521', 'r', '8181', '1861', '2697', '4507', '1229', 'n', 'e', '5649', '9121', '6811', 'j', '7207', '4545', '5871', '3041', 'k', '7883', 'r', 'g', 'r', '9523', '1023', 'd', 'o', '8865', '757', 'k']

SOLUTION:
d, e, g, j, k, n, o, r