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', 'e', '6509', '1295', 'u', '5445', '1731', '3049']

Ex Output:
c, e, u


Ex Input:
['1931', 'c', 's', '8767', 'z', '8977', '9249', '365', 'p', '7187', 'p', '961', 'k', 'k', '423', '5999', '4697', '6251', '6441', '1821', 's', 's', 'f', '5365', 'z', '5113', 'y', 'k', 'i', '5627', 'u', 'w', '4103', '8035', '7105', 'o', 'n', 's', 'y']

Ex Output:
c, f, i, k, n, o, p, s, u, w, y, z


Ex Input:
['l', 'z', '5071', '8079', '2305', '4075', '6989', 'f', 'n', '851', 'h', '9703', '5717', '9997', 'z', '8583', '5019', 'j', 'j', '5081', 'e', '4955', 'a', 'k', '2843', 'k', 'i', 'z', 'e', 'p', 'o', 'd', 'd', 'n', '7787', '9899', '5899', 'j', '6511', 'y', 'y']

Ex Output:

a, d, e, f, h, i, j, k, l, n, o, p, y, z