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:
['c', 'e', '6509', '1295', 'u', '5445', '1731', '3049']

Ex Output:
c, e, u


Ex Input:
['7677', '4069', 'b', 'w', '4381', 'b', '5757', '711', '765', '8347', '6547', '9527', '945', '5333']

Ex Output:
b, w


Ex Input:
['r', 'z', 'f', '871', 'e', '2343', 'z', 'l', 'm']

Ex Output:

e, f, l, m, r, z