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: ['2943', 'k', '8519', '9103', 'j', '2461', '1049', '2211', '8761', 'l', 'e', '8939', '6013', 'r', '9089', '5781', '5383', '5495', '6699', '7307', '2733', '933', '9865', 'g', '6471', '3179', 'm', '8231', 't', 'e', 'u', '9909', 'g', 'g', '9431', '6521', 'y', 'g', '1415', 'e']

SOLUTION: e, g, j, k, l, m, r, t, u, y

PROBLEM: ['8559', '2901', '9011', '9631', 'z', 'p', '6925', 'e', 'g', 'd', 't', 'z', '8817', '2359', 'g', '7515', 'e', '8669', 'e', '6817', 'p', 's', 'w', 'f', '1333', 'n', '9117', 's', 'l', '6039', '1243', 'c', 'p', 's', '8521', 'g']

SOLUTION:
c, d, e, f, g, l, n, p, s, t, w, z