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:
['895', '2049', '8839', '1773', 'v', '467']
answer:
v


question:
['3043', 'r', 'm', 'i', '2653', 'i', '1703', '1125', '6299', '4863', 'n', 'h']
answer:
h, i, m, n, r


question:
['d', 's', 'c', '6727', '5865', '4789', '3091', '7747', 'd', 'k', '4139']
answer:

c, d, k, s


