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:
['o', 'd', '6495', '5211', '341', 'v', '385', 'v', 'g', 'v', 'l', '7631', '2675', 't']
answer:
d, g, l, o, t, v


question:
['8975', '7199']
answer:
-1


question:
['i', 'a', 'r', 'r', '1267', 'k', 'f', '9151', 'o', 'f', '3469', 'n', '9523', 's', 'i', '5663', '5983', '867', 'n']
answer:

a, f, i, k, n, o, r, s