Part 1. Definition
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.
Part 2. Example
['8129', 'a', '4245', 'y', 'm', 'a']
Answer: a, m, y
Explanation: Here, the unique alphabets in the list are 'a', 'y', and 'm', hence their sorted order is 'a, m, y'.
Part 3. Exercise
['2307', 'c', '7071', 'd', '1387', 'g', 'q', 'y', '7009', '5407', 'x', '5019', 's', 'l', '97', '4223', 'f', '7983', '1877']
Answer:
c, d, f, g, l, q, s, x, y