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: ['333', 'b', '261', 'k', 'p', '7861']

SOLUTION: b, k, p

PROBLEM: ['y', 'i', '257', '3695', 's', '6717', '4817', '4117']

SOLUTION: i, s, y

PROBLEM: ['8277', '995', 'e', '5861', '4551', '7167', '5175', '1009', '1311', 'r', '5101', '5739', 'w', 'y', 'g', '2633', 't', '3687', '3867', '1483', '5031', 'x', '1075', '6683', 'c', 'p']

SOLUTION:
c, e, g, p, r, t, w, x, y