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.
--------
Question: ['6643', '6757', 'h', '1033', 's', 'c', '2003', 'p', '5483', 'f']

Answer: c, f, h, p, s


Question: ['p', 'g', 'q', 'e', '8045', '9999', '9555', '7995', '7195', 'z', 't', '5223', '3699', 'i', '4797', '3817', 'x', 'y', 'w', 'o', '8915', '7803', 'n', '1117', 'c', '9647', 'p', 'e', '9669', '4845', '9255', '4545', '3693', '6871', 'w', '4327', '3285', 'k', 'f', 'x', 'i', 'b', '5967', '6601']

Answer: b, c, e, f, g, i, k, n, o, p, q, t, w, x, y, z


Question: ['n', 'j', 'k', 'w', 'q', 'q', 'l', '3453', '5905', '755', 'r', 'h', '449', '363', 'v', 'g', 'r', '2571', '5935', '6017', 'l', 'x', 'f', 'y', 'b', '7899', 'w', 'w', '1029', 'p', '7343', 'p']

Answer:
b, f, g, h, j, k, l, n, p, q, r, v, w, x, y