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:
['x', 'i', 'k', 'c', 'f', '3057', '481', '5887', '847', 'c', 'x', 't', 'g', '5805', 'a', 'i', '2885', '403', 'x', 'c', '4815', '2765', 'c', '5181', 'l', 'e', '3843', '1171', 'u', '7867', 'z', 'e', '9349', '5011', 'h', 'x', '3193', 'i', '4595', '8621', '6007', '1879']

Ex Output:
a, c, e, f, g, h, i, k, l, t, u, x, z


Ex Input:
['n', '7337', '6887', '2203', '4663', '2837', '6451', '959', '8027', 'p', 'v', 'q', 'g', '8059', '6151', 'v', '7097', '6583', '7637', '2367', 'w', '9603', '5365', '3773', '1707', 'k', 'x', 's', 'c', 'u', '3641', '6137', '1207', 'k', '5531', '4543']

Ex Output:
c, g, k, n, p, q, s, u, v, w, x


Ex Input:
['z', 'z', '4973', 'p', '1877', 'i', '9461', 'v', '5437', '1933', '3131', 't', 's', '131', 'n', 'w', '3661', 'q', 'a', 'x', 'y', '2739', 'c', 'v', 'w']

Ex Output:

a, c, i, n, p, q, s, t, v, w, x, y, z