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:
['s', 's', '6581', 'e', '7355', '1315']

Ex Output:
e, s


Ex Input:
['2453', 'r', 'd', '8499', 't', 's', 'h', 'a', 'm', '9271', 'g', '2599', '6209', 'o', 'i', '4069', 't', '6793', '7679', '6643', '7359', 'm', 'f', 'w', '775', '3347', '6161', '9745', 'i']

Ex Output:
a, d, f, g, h, i, m, o, r, s, t, w


Ex Input:
['981', '1429', '7393', 'l', 'o', 'j', '1297', '8429', '3943', '7827', 'b', '7377', '51', 'r', '3705', '3981', '3719']

Ex Output:

b, j, l, o, r