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:
['3995', 'n', 'z', '8389', '7857', '3005', 'i', 'e', '1117', 'z', '8251', 'r', 't']

Ex Output:
e, i, n, r, t, z


Ex Input:
['2819', 'k', 'u', 'a', '4575', 'a', 't', 'a', 'f', '1507', '415', 'w', 'o', 'o']

Ex Output:
a, f, k, o, t, u, w


Ex Input:
['7477', 'b', 'v', '6813', '2891', '1297', 'l', 'c', 'b', 's', 'g']

Ex Output:

b, c, g, l, s, v