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:
['5075', '9169', '4659', '7605']

Ex Output:
-1


Ex Input:
['u', '635', '5249', '9457', 's', '9317', '9407', 'l', 'w', '9705', 'k', '429', '5489', 'e', 'd', '2457', 'o', '4665', '1675', 'l', 'y', 's', 'o', 't', '4285']

Ex Output:
d, e, k, l, o, s, t, u, w, y


Ex Input:
['j', '6721', '7273', '5287', '7399', '3899', '7549', 'y', 'g', '2227', 't', 'p', 'u', '93', 'y', 'k', '4673', '3603', 'p', '9133', '5693']

Ex Output:

g, j, k, p, t, u, y