instruction:
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:
['9425', 'l', 'c', 'n', '5925', '2543', '3935', 'c', '7533', 'j', 'q', '3775', '5897', '9435', '69', 'e']
answer:
c, e, j, l, n, q


question:
['6643', '6757', 'h', '1033', 's', 'c', '2003', 'p', '5483', 'f']
answer:
c, f, h, p, s


question:
['w', '6573', '3549', '5683']
answer:

w