instruction:
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.
question:
['g', '8591', '4463', '2189', '7901', '1457', 'f', 'i', '9031', 'r', '5519', '3955', 'd', '2093', 'c', 'y', '6591', '6463', 'h', '4371', '111', 'p', '3221', '4185', 'p', '8761', 'w', 'p']
answer:
c, d, f, g, h, i, p, r, w, y

question:
['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']
answer:
e, f, l, n, p, q, r, s, w, y

question:
['h', '9705', '6607', '3167', '6437', 't', '5093', 'v', 'n', '537', '203', '697', '7969', '6615', '2057', '4445', 't', 'e', '8955', 'w', 'h', 't', 'd', 'f', '8171', 'w', '4347', '339', 'z', '1679', 'q', '8073', 'k', '6809', '47']
answer:
d, e, f, h, k, n, q, t, v, w, z