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: ['5193', 'h', 'm', '703']

SOLUTION: h, m

PROBLEM: ['477', '3931', 'g', '5967', 'm', '9845', '1607', 'a', '1749', 'k', 'j', '7945', '9125', 'v', 'n', 's', '5185', '1117', '17', 'x', '4149']

SOLUTION: a, g, j, k, m, n, s, v, x

PROBLEM: ['6033', 'r', '6287', 'j', 'v', '3045', '1283', 'x', '9731', 'h', 't', '5885', '6735', 'e', '861', '3007', 'k', '6973', '333', '4961', '8233', '9575', 'm', '2809']

SOLUTION:
e, h, j, k, m, r, t, v, x