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:
['7055', '2573', '1713', 'x', 'm']

Ex Output:
m, x


Ex Input:
['3627', '2051', '3203', 'c', 'r', 'a', '1453', 'e', 'z', 't', '1093', '4651', 'a', 'f', '8159', '9623', 'l', 't', 'r', '6963', '7071', '8103', '3493', 'y', '2369', '609', '2011', 'f', '187', 'f', 'c']

Ex Output:
a, c, e, f, l, r, t, y, z


Ex Input:
['y', 'd', '3499', '4549', '27', '8381', 'z', '485', '6773', '1611', 'z']

Ex Output:

d, y, z