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:
['s', 's', '6581', 'e', '7355', '1315']
answer:
e, s


question:
['h', 'b', '9601', 'h', 'h', 'h', '8099', '8265', 'i', 'd', '8791', 'p', '8059', '4309', '501', '2581', '9837', '157', '4785', '5925', 'q', '8491', '4779', 'r', 'l', 'k', '3679', 'v', 'g', 'g', '9731', '1909', '9783', 'f', '4293', '5009', 'o', '3057', '3157', 'c', '5587', 'b', 'f', 'd', 'k']
answer:
b, c, d, f, g, h, i, k, l, o, p, q, r, v


question:
['6313', '5865', '5833', 'q', 'o', 'z', 'g', 't', 't', 'd', '793', '5455', '6269', '2097', '2833', 'c']
answer:

c, d, g, o, q, t, z