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: ['3019', 'g', 'q', 'u', '611', 'z', '3671', '8119', '1679', 'h', '2631', '655', 'k', '2837', 'e', 'f', 'e', 'f']

SOLUTION: e, f, g, h, k, q, u, z

PROBLEM: ['7777', '6223', 'k', 'k', 'd', '9743', '189', '7705', 'c', '6115', '4275']

SOLUTION: c, d, k

PROBLEM: ['d', 'b', '8627', 'd', 'g', '5975', 'd', '5397', 'i', '7807', '705', 'y', '3067', 'y']

SOLUTION:
b, d, g, i, y