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: ['1233', '405', '8901', '7147', '8841', 's', 'v', '3131', 'p', 'd', 'y', '5873', '439']

SOLUTION: d, p, s, v, y

PROBLEM: ['7799', '8163', '3389', 'x', 'k', 'm', '6085', 'f', '1131']

SOLUTION: f, k, m, x

PROBLEM: ['t', '7167', 'g', '8701', 'e', '1751', 'e', '7781', '5901', '1519', '5901', '207', '3165', 'z']

SOLUTION:
e, g, t, z