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:
['a', '2579', 'f', '6787', '123', '225', '6499', '4419', 'o', '1785', '7981', 'z', 'b', '2441', '2821', 'o', 'k', '2747', 's', 'u', 'q', '3901', '7629', 'k', 'm', 'q', '6577']

Ex Output:
a, b, f, k, m, o, q, s, u, z


Ex Input:
['333', 'b', '261', 'k', 'p', '7861']

Ex Output:
b, k, p


Ex Input:
['3147', '7043', '5389', 'f', '4879', '5165', 'd', 's', '2483', '9239', '7507']

Ex Output:

d, f, s