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 input: ['8129', 'a', '4245', 'y', 'm', 'a']
Example output: 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'.
Q: ['h', 'q', '6941', 'e', '2661', '223', 'c', '3369', 'm', '7963', 'p', 'l', 'k', 'd', '6041', 'w', 'z', '5231', '9033', '3909', '5019']
A:
c, d, e, h, k, l, m, p, q, w, z