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:
['7989', '6897', 'o', 'v', '5687', '2933', 'w', '8207', 'y', 's', 'w', '3013', 'h']
answer:
h, o, s, v, w, y


question:
['4423', '8295', 'h', '4881', 'j', 'c', '1185', 'z', 'm', '2725', 'p', '9187', '6275', '1617', '2523', '9879', '4149', '2197', '3909', '5155', '691', 'r', 'e', 'u', 'l', 'd', '1581', '2763', 'c']
answer:
c, d, e, h, j, l, m, p, r, u, z


question:
['r', '431', '5369', '2213', 'y', 'r', 'k', '1431', 'n']
answer:

k, n, r, y