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', '6003', 'k', '1987', '1877', 'a', '2615', 'n', 's', 'f', 'b', 'm', '1149', '8293', '5803', 'e', '2697', '5917', 'p', '6035', '2385', 'i', 'u', 'm', '9565', '4523', 'b', 'v', '2577', '9725', '6093', '6203', '4197', '8477', 'o', 'd', '3637', '9827', '5523', '7189', 'j', '8893', 'h', 'q']

SOLUTION: a, b, d, e, f, h, i, j, k, m, n, o, p, q, s, u, v

PROBLEM: ['3583', 'd', '1481', 'w', 'l', '7261', '2933', 'n', '8725', 'g', '3441', 'r', '287', '7327', '5637', 'r', '5389', 'm', 'j', 'd', 'a', 'e', 'v', '7879', '1731', 'z', '43', 'q', 'p', '4315', 'p', '3651', 'o', 'l', 's', '9787', 'h', '6735']

SOLUTION: a, d, e, g, h, j, l, m, n, o, p, q, r, s, v, w, z

PROBLEM: ['t', 'v', 'm', 't', 'k', 's', '9379', 'k', '3995', '3957', 'd', '3859', '6279', 'u', '6877', 'g', 'u', 'g', 'p', '3383', '7849', '8129', 'e', 'f', 'e', 'm', '1645', 'c', '6705', '9641', 'c', '9743', 'w']

SOLUTION:
c, d, e, f, g, k, m, p, s, t, u, v, w