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.

['6249', '1235']
-1

['n', '6615', 'r', 'q', '3803', '4641', '9775', '7719', 'n', '6571', '2723', '6919', 'e', 'f', '1919', '6963', '2581', 'y', '713', 'w', 'w', 'w', 'l', 's', '3993', '9563', '9365', '9277', '103', '2737', 'y', '6005', '9763', 'p', '261']
e, f, l, n, p, q, r, s, w, y

['y', 't', 'f', 's', '8265', 'v', '7799', '4619', 'l', 'k', 'r', 'c', '9005', '1457', '2223', '8753', '9297', '8533', '8081', '8317', 'p', '8507', 'p', 'v', 'y']

c, f, k, l, p, r, s, t, v, y