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: ['y', 'u', 'c', '5909', 'x', '9865', 'e', 'h', '5125', '4719', 'w', '8855', 'i', 'd']

Answer: c, d, e, h, i, u, w, x, y


Question: ['h', 'l', 'i', '1507', 'h', '409', '6777', 'u', '5563', '6113', '6513', '9949', '461', 'z', 'm', '2519', 'r', '4699', 'n', 'x', '4645']

Answer: h, i, l, m, n, r, u, x, z


Question: ['y', '5287', '9523', '8211', '2569', 'c', 'y', 'g', 'r', 'k', '7341', '8631', 'p', 'y', '9497', 'i', 'c', 'x', '6671', '9071', 'w', '697', '5009', '8127', 'j', '6737', '797', 'b', '5087', 'y', 'n', 'f', '8585', 'h', 'g', 'x', 'g', 'z', '8781', '8243', 'y', 'd']

Answer:
b, c, d, f, g, h, i, j, k, n, p, r, w, x, y, z