Detailed Instructions: 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.
See one example below:
Problem: ['8129', 'a', '4245', 'y', 'm', 'a']
Solution: a, m, y
Explanation: Here, the unique alphabets in the list are 'a', 'y', and 'm', hence their sorted order is 'a, m, y'.

Problem: ['x', '9721', 'd', 's', '5847', 'e', '571', '6851', 'p', '3125', '9961', 'r', 'o', 'f', '6525']
Solution:
d, e, f, o, p, r, s, x