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: ['o', '3093', '9949', 'x', '8217', '4025', 's', 'p', 'v', '6511', 'c', 'n', 't', 'v', 'j', '1645', '4215', 'c', '3441', 't']
Solution:
c, j, n, o, p, s, t, v, x