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: ['d', '1989', '6365', 'y', 'm', '1245', '7539', 'm', '3787', '6987', 'e', 'e', 'y', '9577', 'b', '5', '8179', 'x', '2853', '6337', 'w', 'f', 'b', 'q', '563', '6077', '1133', 'x', '6045']

SOLUTION: b, d, e, f, m, q, w, x, y

PROBLEM: ['5971', 'x', 'c']

SOLUTION: c, x

PROBLEM: ['b', '1789', 'k', 't', 'v', '1905', '4455', '7827', 'j', '249', 'r', 'z', '1005', 'o', '6851', 'i', 'c', 'x', 'h', 'k', '8185', 'w', 'd', 'r', 'i', 'c', '3857', 'z']

SOLUTION:
b, c, d, h, i, j, k, o, r, t, v, w, x, z