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', 'g', '9019', '9987', '8713', '9513', 'a', '2043', 'd', '5817', 'w', 'd']

SOLUTION: a, d, g, w

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: ['6589', '5129', '5953', 'q', 'r', 'h', '1509', 'y', 'y', 'o', '1541', '8089', 'b', 'h', '3077', '6197', 'n', 'x', 'm', 'v', 'n', 's', 'j', 'l', 'u', '467', 'i', '7483', '1417', '5225', 'a', 't']

SOLUTION:
a, b, h, i, j, l, m, n, o, q, r, s, t, u, v, x, y