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:
['7777', '6223', 'k', 'k', 'd', '9743', '189', '7705', 'c', '6115', '4275']

Ex Output:
c, d, k


Ex Input:
['7799', '8163', '3389', 'x', 'k', 'm', '6085', 'f', '1131']

Ex Output:
f, k, m, x


Ex Input:
['r', 'z', 'b', '8041', 'y', 'j', 'p', 'z', 'r', '3219', '3083', '477', '867', '835', '6615', '4931', '5941', 'm', '8089', 'y', '2053', '7785', '7127', 'q', 'g', '7697', 'i', '8333', 'd', '6343']

Ex Output:

b, d, g, i, j, m, p, q, r, y, z