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:
['1983', '1835', '6543', '6399', '4177', '9385', '7127', 'p', 'l', 'u', 'g', 't', '3423', 'g', 'b', 'l', '3133', '2429']

Ex Output:
b, g, l, p, t, u


Ex Input:
['z', '8763', '6399', '45', '6731', 'v', '441', '4763', 'u', '8741', 'r', '9143', 'd', 'p', '2241', 'y', '6523', 'y', 'w', '6771', 't', 'r', '9239', '295', 'z', '461', 'b', '9217', '2597', '1249', 'r', 'i']

Ex Output:
b, d, i, p, r, t, u, v, w, y, z


Ex Input:
['5043', '2705', '7735', 'z', 'u', 's', 'd', 'z', '2895', '3079', 'p', 'e', '2461', 'z', 'a', '6983', 'g', 'h', 'j', '2711', 'u', '1035', 'm', 'a', '4503', '7105', '4769', 'g', 'v', 'm', 'z', '5635', '9735', '8215', '9273', 'k', 'r', 't', '6913', '4663', 'l', '5011']

Ex Output:

a, d, e, g, h, j, k, l, m, p, r, s, t, u, v, z