Teacher: 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.
Teacher: Now, understand the problem? If you are still confused, see the following example:
['8129', 'a', '4245', 'y', 'm', 'a']
Solution: a, m, y
Reason: Here, the unique alphabets in the list are 'a', 'y', and 'm', hence their sorted order is 'a, m, y'.

Now, solve this instance: ['h', '9705', '6607', '3167', '6437', 't', '5093', 'v', 'n', '537', '203', '697', '7969', '6615', '2057', '4445', 't', 'e', '8955', 'w', 'h', 't', 'd', 'f', '8171', 'w', '4347', '339', 'z', '1679', 'q', '8073', 'k', '6809', '47']
Student:
d, e, f, h, k, n, q, t, v, w, z