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:
['f', '7573', '2067', 'n', '3671', '7969', '7889', '4893', '6501', 'l', 'y', '4331', 'a', 'e', '2081', '3863', 't', 'j', '7921', 's', '7203', '7797', 'f', '4279', '1299', '987', '5003', '9071', '9559', '6061', '1889', '2653', 'm', 'w', '665', '7343', '9763', 'r', '6343', '9393', '9289']
answer:
a, e, f, j, l, m, n, r, s, t, w, y


question:
['j', 'r', 'z', 'f', '1485', '2419', 't', 'd', '6023']
answer:
d, f, j, r, t, z


question:
['a', 'c', '6861', '6491', '5749', 'b', 'l', 'm', 'l']
answer:

a, b, c, l, m