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: ['6143', '9073', 'h', '1459', 'q', '5799', '6555', '525', '7921', '5041', '3273', '383', 'd', '9075']

SOLUTION: d, h, q

PROBLEM: ['2995', '8179', '8131', '5655', 'j', 'q', 'l', '3193', '1823', 'y', 'n', '7645', 's', '5665', 'r']

SOLUTION: j, l, n, q, r, s, y

PROBLEM: ['e', 'x', '1679', '7759', '6679', '4075', 'w', 'd', '5901', '733', 'x', '2307', 'q', 'o', '6823']

SOLUTION:
d, e, o, q, w, x