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:
['8489', 'h']

Ex Output:
h


Ex Input:
['3743', '765', '5299', '3069', '8547', '8991', '1811', 'k', '5557', '4907', '5907', 'd', 'r', 'z', '5385', '5463', 'f', '2063', 'm', '3419', 'k', '3897', '4049']

Ex Output:
d, f, k, m, r, z


Ex Input:
['9039', '9509', 'r', 'w', 'd', '4419', '7721', 'd', '6039', '1755', '1867', 'r', '491', 'a', 'a', '1609', 'f', '5717', '7871', 'n', '7581', 'z', 'b', 'z', 'r', '6423', 's', '1965', 'i', 'i', 'x', '1093', '5933', '2661', '6485', 'j', '1427', '8521', 'd']

Ex Output:

a, b, d, f, i, j, n, r, s, w, x, z