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: ['p', '6123', '6961', 't', 'p', 'h', '9035', 'r', '6341', 'x', '3635', '5885', 't', '3543', '9567', '1787', 'o', '2991', 'k', '3441', '4091', 'a', 'r', '423', '9383', '7147', 'h', '663', 'd']

SOLUTION: a, d, h, k, o, p, r, t, x

PROBLEM: ['1197', '305', 's', '1113', 'n', '2207', 'e', '227', '2833', '607', '3049', 'v', '4615', 'a', 'k', 'r', 's', '3571', 'f', '4215', 'f', '8985', '5559', '4111', 'u', '1433', '1943', '8831', 'w', 'x', 'o', '9023', 'u', 'y', 'p', 's', 'h', '8877', 'p', 'n', '8903', '5811']

SOLUTION: a, e, f, h, k, n, o, p, r, s, u, v, w, x, y

PROBLEM: ['n', 'm', '4393', '9437', 'x', '9365', '9909', '6673', '2565', 'w', 'b', '725', '257', '4593', '555', '9055', 'f', '5355', 'y', '5789', '7109', 'k', 'c', '9595', 'r', 'v', '1775', 'm', '4581', 'j', '8579', '6107', '6747', '943', 't', 'j', '5637', '299', 'v', 'e', 'l', 'l', 'h']

SOLUTION:
b, c, e, f, h, j, k, l, m, n, r, t, v, w, x, y