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:
['v', '2989', 'z', '7843', 'e', '9923', 'y', 'b', '7611', 'u', 'u', '6227', '3145', 'w', '6451', 'g', '3129', 'o', 'r', 'z', '8349', 'u', 'h', 'd', 'g', 'a']
answer:
a, b, d, e, g, h, o, r, u, v, w, y, z


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:
['y', 'd', 'r', 'v', '7195', '7863', '3635', 'n', '9561', 't', '3155', '315']
answer:

d, n, r, t, v, y