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.

Ex Input:
['1945', 't', '4477', '4439', '6569', '2021', 'y', 't', '2725', '8947', '6921', '1373', '8107', 'g', 'c', 'w', 'x', 'b', '9117', 'k', '6567', '5073', '2307', 'e', 'b', '7405', 'e', 'x', '1419', 'd', 'o', 'n', 'a', '2647', 'z', '1459', 'n', '6137', 'u', 'b', 'q', '4459']

Ex Output:
a, b, c, d, e, g, k, n, o, q, t, u, w, x, y, z


Ex Input:
['6769', '1057', '1021', 'n', '8231', '9173', '8123', 'a', '6053', 'q', 'y', '883', 'r', '1215', 'x', 'o', '9531']

Ex Output:
a, n, o, q, r, x, y


Ex Input:
['u', '1743', 't', 'n', '6215', 'c', 'q', '5555', '1611', '2253', 'g', 'l', 'k', '459', 'j', '8545', 'k', 'r', '629', 'w', '3713', '4533', '1223', '1373']

Ex Output:

c, g, j, k, l, n, q, r, t, u, w