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:
['7561', 'r', '3419', 'k', 's', '5997', 'u', '6635', '7003', '8491', 'i', '9835', 'c', '8827', 'h', 'a', 'j', '7675', '1995', '1223']

Ex Output:
a, c, h, i, j, k, r, s, u


Ex Input:
['4891', 'a', '3155', 's', '7607', 'j', '1851', '2557', '699', 'e', 'y', '3755', 'x', 'x', 'e', '4027', 'u', '8835', '6607', 'u', 'a']

Ex Output:

a, e, j, s, u, x, y