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


question:
['g', '4165', 'n', 'w', 'n', 'e']
answer:
e, g, n, w


question:
['o', 'c', 'j']
answer:

c, j, o