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.

Q: ['w', '743', '5757', '8731', 'k', 'p', '317', 'n', 'x', '5649', 'l', 'm', 'c', '2499', 'l']

A: c, k, l, m, n, p, w, x
****
Q: ['t', 'r', '2959', '2517', 'a', '9959', '729', '511', 'y', 'r', '465', 'c', '687', 'm', 'b', 'm', '3449', '9713', 'g', '8275', '8823', 'a', 'z', 'w', '2185', '6283', '8457', '8137', '7163', '8329']

A: a, b, c, g, m, r, t, w, y, z
****
Q: ['471', '4983', '379', '4825', '9435', 'h', 'd', '7603', 'z', 'd', 'z', 'b', 'f', '8037', 'z', 'e', 'f', '9991', '1965', '2667', 't', 'm', 'y', '3917', 'l', 'f', '1877', '6985']

A:
b, d, e, f, h, l, m, t, y, z
****