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:
['6175', '9441', '7127', '5979', 's', '1367', 'e', 'm', '7083', '1787', '8375', '2851', '3475', 'r', '697', 'g', 'z', 'm', '4207', 'c', '7971', 'z', '9339', 'd', 's', '3507', '9003', 'i', 'y', 'w', 'j', 'i']

Ex Output:
c, d, e, g, i, j, m, r, s, w, y, z


Ex Input:
['2527', '9123', '8717']

Ex Output:
-1


Ex Input:
['v', 'h', 'y', 'a', '5723', 'e', '1635', 'd', 'q', '1619', 'u', 'z']

Ex Output:

a, d, e, h, q, u, v, y, z