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.

Example input: ['8129', 'a', '4245', 'y', 'm', 'a']
Example output: a, m, y
Example explanation: Here, the unique alphabets in the list are 'a', 'y', and 'm', hence their sorted order is 'a, m, y'.
Q: ['q', '555', '4063', '7915', '9621', '485', 'c', 'e', 'd', '3535', 'x', 's', '347', 'b', '5885', '2829', 'k', 'c', 't', 'v', 'q', 'p', '2959', '8993', 'r', 'o', 'r', 'c', '4405', '61', 'a', 'n', '1391', 'w', '1693', '7241', '8691', '5553', 'd', '995']
A:
a, b, c, d, e, k, n, o, p, q, r, s, t, v, w, x