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: ['5957', 'd', 'i', 'b', 'e', '5565', 'c', 'i', '2919']

SOLUTION: b, c, d, e, i

PROBLEM: ['4787', 'c', '1727', '9863', '8147', '3931', 'b', '1133', '3023', '7427', '7837', 'n', '7921', 'o', 'c', '3973', '1949', 'x', 'g', 'b', 'd', '8559', '8661', '4465', 'z', '369', 'q', 'e', 'y', '8629', '7665', 'i', 'r', 'n', 'z', '9115', '1393', '4899']

SOLUTION: b, c, d, e, g, i, n, o, q, r, x, y, z

PROBLEM: ['q', 'h', 'w', '4761', 'b', '1223', 'q', '2587', '6769', '4745', 'u', 'h', '1', 'k', 't', 'h', 'h', 'p', 'x', 'x', '8857', '8259', '1593', '8919', '4673', 'x', 'f', '2353', '7233', 'g', '6857', '7419', 'x', 'e', '7153', 'z', '2255']

SOLUTION:
b, e, f, g, h, k, p, q, t, u, w, x, z