You will be given a definition of a task first, then some input of the task.
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.

['4027', 'e', 'z', 'i', 'c', '3863', '8221', 'd', '509', '6371', '7813']
Output:
c, d, e, i, z