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:
['m', '6761']
answer:
m


question:
['d', '1625']
answer:
d


question:
['b', '2567', '1571', 'h']
answer:

b, h


