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:
['7595', '5303', '3985', 'n', 'w', 's', 'r', 'f', '8237', 'q', 'y', 'f', '3121', '2463', '4597', 'q', '6801', 'f', 'i', '8563', '3267', 'k', '6157', 'f']

Ex Output:
f, i, k, n, q, r, s, w, y


Ex Input:
['6249', '1235']

Ex Output:
-1


Ex Input:
['m', '5797', 'w', '2163', 'g', 'b', '1159', 'x', 'p', 'k']

Ex Output:

b, g, k, m, p, w, x