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:
['2697', 's', '8733', 'n', '5871', 'f']

Ex Output:
f, n, s


Ex Input:
['d', '2359', '6571', 'c', 'n', 'u', '9513', '9321', '1689', 'b', '969', '1823', 'e', 'b', '9147', 's', '1811', 'k', '5443', '8699', '5483', 'v', 'w', 'n', '1215']

Ex Output:
b, c, d, e, k, n, s, u, v, w


Ex Input:
['t', '1493', 'o', 'j']

Ex Output:

j, o, t