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: ['8129', 'a', '4245', 'y', 'm', 'a']
Example solution: 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'.

Problem: ['o', 'n', 'd', 'h', 'r', '4373', 'u', '219', '4449', '9657', '1435', '3581', 'y', '467', '6923', 'l', 'g', '1521', '7739', '163', '4175', '619', '5327', 'n', '6737', 'y', '5545', '8381', '8387', 'l', 'd', '5519', 'a', 'q', '8155']

Solution: a, d, g, h, l, n, o, q, r, u, y