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: ['1593', '8165', 'q', '6689', 'b', 'r', '373', 'g', '6505', '415', '495', 'j', 'j', 'f']

SOLUTION: b, f, g, j, q, r

PROBLEM: ['w', '8777', 'y', 'e', '8015', 't', 'w', '53', '9149', 'e', 'k', '1837', 'b', 's', '4007', '4905']

SOLUTION: b, e, k, s, t, w, y

PROBLEM: ['73', 'l', 'g', '221', 'q', '6011', '1001', '539', 'h', 'z', '7777', 'p', 't', 'v', 'y', 'o', 'o', '4839', '2317', 'k', '7613', 'f', '5985']

SOLUTION:
f, g, h, k, l, o, p, q, t, v, y, z