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:
['5761', '2289', '577', 't', '125', 'i', 'g', '9693', '747', 'd', '4829', '9587', 'f', 'k', 'w', 'v', '8607']

Ex Output:
d, f, g, i, k, t, v, w


Ex Input:
['7591', '1403']

Ex Output:
-1


Ex Input:
['f', 'r', '701', 'u', '3335', 't', '829', '6937', '9613', 'b', 'i', 'w', 'z', '7053', '9013', '7653', '6323']

Ex Output:

b, f, i, r, t, u, w, z