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: ['u', 'i', '1185', '3795', '5417', 'k', 'b', '2629', '2635', 'z']

SOLUTION: b, i, k, u, z

PROBLEM: ['a', '533', '67', 'z', 'z', '9283', 'o', 'a', '7045', '1521', 'm', 'h', 'q', '4173', '7497', '319', '5721', '6097', 'i', '9829', '1801', '7347', 'r', 'z', '239', '4279', 'e', 'k', 'r', 'v', '6653', '599', '8597', 'd', 'r']

SOLUTION: a, d, e, h, i, k, m, o, q, r, v, z

PROBLEM: ['6643', '7515', '6327', 'p', '8023', 'h', '1865', '969', 'y', 'm', 'u', '441', '3471', 'j', '8883', 'c', 'z', '5869', '389', '7809']

SOLUTION:
c, h, j, m, p, u, y, z