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

Problem: ['j', 'm', '439', '635', 'z', '3385', 'e', '6257', 'h', '251', 'g', '6441', 'p', '589']

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Solution: e, g, h, j, m, p, z