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:
['r', 's', '2471', 'n', '635', 'k', '3551', '7041', '8765', '1221', '8439', '7773', '6471', 'u', 'p', '2093', '6479', '1435', '6881', 'a', 'y', 'm', 'r', '1627', 'w', 'k', 'b', '3095', '9059', '285', 'y', 'a', 'm', 'x', '637', 'i', '3407', 'e', 'e']

Ex Output:
a, b, e, i, k, m, n, p, r, s, u, w, x, y


Ex Input:
['i', '9215', 'n', 'p', '4815', '8757', 'm', '1755', 'c', 'z']

Ex Output:
c, i, m, n, p, z


Ex Input:
['1251', '7883', '8149', 't', '7407', 'f', 'e', 'f', 'w', 's', 'p', 'k', 'v', 'n', 's', '7745', 's', 'g', 'n', '4487', 'n', 'i', 'b', '5315', '6715', 'x', 'j', 'n', 'i', 'v', '2753', '9013', 'x']

Ex Output:

b, e, f, g, i, j, k, n, p, s, t, v, w, x