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: ['4993', 'n', '7115', 'f', 'd', 'q', '249', '3203', 'w', '5689', '4103', '7129', '603', 'e', 'z', '5571', '3241', '6029', '2721', '8451', 'o', '7841', 'p', '6271', 'r', 'b', '9481', '4045', 'v']

SOLUTION: b, d, e, f, n, o, p, q, r, v, w, z

PROBLEM: ['8887', '1199', 'r', '7209', 'k', '7567', '7239', 'k', '5123', 'w', '4523', 't', 'd', '5289', '5737', '485', 'w', 't', '7651', 'v', '7213', '7687', 'y', 'w', '7265', 'b', 'b', '3667', 'z', '9935', 'i', 'l', 'u', '6715', 'j', '9815', '8925', '7941', 'w', 'm', '3907', '621', '5523', '5849']

SOLUTION: b, d, i, j, k, l, m, r, t, u, v, w, y, z

PROBLEM: ['9005', 'm', 'd', '9319', '6273', 'y', 'i']

SOLUTION:
d, i, m, y