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:
['m', '5005', 'y', 'h', 'w', '3609', 'p', '2539', '3307', 'p']

Ex Output:
h, m, p, w, y


Ex Input:
['c', '1693', 'l', 'u', 'x', '3609', 'h', '4159']

Ex Output:
c, h, l, u, x


Ex Input:
['1297', 'm', '3859', '9393', 'v', '6463', 'g', '6887', '3799', 'q', '8539', 'x', '5471', 'a', '1207']

Ex Output:

a, g, m, q, v, x