You will be given a definition of a task first, then an example. Follow the example to solve a new instance of the task.
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.

['8129', 'a', '4245', 'y', 'm', 'a']
Solution: a, m, y
Why? Here, the unique alphabets in the list are 'a', 'y', and 'm', hence their sorted order is 'a, m, y'.

New input: ['y', 'w', 'x', '8645', '2119', '5917', 'p', '8691', 'y', '2499', '59', 's', '9419', '5083', '3385', '483', '7679', 'i', '6435', 'l', 'c', 'f', 'd', '535', '891', '9247', '8175', 'b', 'a', 'x', 'y', '8391', '6359', 'u', 'r', '9933', '9241', 'o', 'a', '9169', 't', '9369', '2319', 'q']
Solution:
a, b, c, d, f, i, l, o, p, q, r, s, t, u, w, x, y