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.
--------
Question: ['y', 'i', '257', '3695', 's', '6717', '4817', '4117']

Answer: i, s, y


Question: ['7203', '8715', '3193', 'w', '7159', '8535', 'i', '2425', 'j', 'f', '6709', 'w', 'w', 's', 'e', '9337', 'r', 'r', '5255', '1707', 'u', '1443', 'e', 'e', 'v']

Answer: e, f, i, j, r, s, u, v, w


Question: ['9665', '7281', 'w', 'h', '2181', '9185', 'o', '9437', '4129', 'f', '6999', 'p', 'p', 'k', 'd', '7415', '5935', '8587', 'q', '6797', '8629', 'c', '5097']

Answer:
c, d, f, h, k, o, p, q, w