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:
['2527', '9123', '8717']

Ex Output:
-1


Ex Input:
['895', '2049', '8839', '1773', 'v', '467']

Ex Output:
v


Ex Input:
['7707', 't', 'e', 'z', '1483', '6855', '1483', 'b', 'w', '8351', 'y', '1699', '8965', 'n']

Ex Output:

b, e, n, t, w, y, z