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: ['1945', 't', '4477', '4439', '6569', '2021', 'y', 't', '2725', '8947', '6921', '1373', '8107', 'g', 'c', 'w', 'x', 'b', '9117', 'k', '6567', '5073', '2307', 'e', 'b', '7405', 'e', 'x', '1419', 'd', 'o', 'n', 'a', '2647', 'z', '1459', 'n', '6137', 'u', 'b', 'q', '4459']

SOLUTION: a, b, c, d, e, g, k, n, o, q, t, u, w, x, y, z

PROBLEM: ['4269', '1847', '2025', '601', 'g', 'n', 'h', '3499', '4977', '3579', '9355', '3489', 'm', 'm', '4401', '4605', 'l', '3977', 'h', 'd', 't', '5135', '7787', 'k', 'q', '7699', '5325', '6269', '1865', 'h', '8915', '5677', 'g', '603', '1435']

SOLUTION: d, g, h, k, l, m, n, q, t

PROBLEM: ['2123', '3751', 'g']

SOLUTION:
g