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: ['q', '6421', 'w', 'x', '669', 'h', '3853', '6609', 'p', '947', 'g', 'c', 'x', '2617', 'v', 'e', '4795', '5755', 'a', '2379', 'y', '5939', 'l', 'h', 'g', '3779', 'c', 'm', '3157', '4027', 'g', '2917', '9461', '7271', 't', 'i', '9807', '147']

SOLUTION: a, c, e, g, h, i, l, m, p, q, t, v, w, x, y

PROBLEM: ['o', 'v', 'w', '7939', '571', '395', '3707', 'm', 'd', 'u', 'o', 'r', '4211', '9645', '8731', '2441', 'y', '8147', '8809', 'e', 'b', '6835', 'i', '2083', 't', '3481', 'f', 'f', '5559', '3601', 'e', '5637', '5185', 't', '6777', '3419', '8637', 'p', 's', 'o', 'x']

SOLUTION: b, d, e, f, i, m, o, p, r, s, t, u, v, w, x, y

PROBLEM: ['7335', 'f', '9819', 'g', 'q', 'h', '1579', '7865', '7679', '4761', '4825', 'r', 'j', '9101', 'y', 'l', 's', '4343', 'w', 'f', '4417', 'k', '2025', '9877', '9563', '447', 'i', 'w', '2659', '1507', 'f', 'x', 'k', '4261', '6541', 'y']

SOLUTION:
f, g, h, i, j, k, l, q, r, s, w, x, y