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:
['c', '7039', 'g', '1899', 'r', '507', 'c', '2587', '3865', '1729', '3927', 'r', '3535', '2791', 'm', 'l', 'r']

Ex Output:
c, g, l, m, r


Ex Input:
['8887', '1199', 'r', '7209', 'k', '7567', '7239', 'k', '5123', 'w', '4523', 't', 'd', '5289', '5737', '485', 'w', 't', '7651', 'v', '7213', '7687', 'y', 'w', '7265', 'b', 'b', '3667', 'z', '9935', 'i', 'l', 'u', '6715', 'j', '9815', '8925', '7941', 'w', 'm', '3907', '621', '5523', '5849']

Ex Output:
b, d, i, j, k, l, m, r, t, u, v, w, y, z


Ex Input:
['w', '743', '5757', '8731', 'k', 'p', '317', 'n', 'x', '5649', 'l', 'm', 'c', '2499', 'l']

Ex Output:

c, k, l, m, n, p, w, x