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: ['s', 'w', 'c', '4137', 't', '2437', '349', 'h', '4539', 't', 'b', 'y', 'q', 't', '9087', 'c', '9489', '6285', '6247', '8353', 'n', 't', '8661', 'p', 'z', 'p', '773', 'w', 'q', '8081', 'r', 'u', 'z', 'k', 'a', 'b', '7513', '5549', '5325', '1101', 's', '6507', '3317']

SOLUTION: a, b, c, h, k, n, p, q, r, s, t, u, w, y, z

PROBLEM: ['653', '1969', '6235', '6283', 'd', 'e', '465', 'e']

SOLUTION: d, e

PROBLEM: ['z', '5983', '7979', 'y', 'o', '5591', 'f', '8877', 'p', '5213', 'n', 'u', 'l', '4077', 'x', 'j', 't', '8703', 'd', 'y', 'd', 'k', '3271', '4215', 's', '5413', 'f']

SOLUTION:
d, f, j, k, l, n, o, p, s, t, u, x, y, z