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: ['q', 'v', 'r', '5967', '2877', 'f', '3407', 'e', '4593', 'k', '2831', '3257', 'k', 't', 'j', 'f', '3947', '7513', 'y', 'g']

Solution: e, f, g, j, k, q, r, t, v, y