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', '1099', 'r', '8995', 'o', '2909']
answer:
o, r


question:
['2047', '4403', 'g', '3017', '1627', 'v', 'r', '2237', '5513', 'o', 'v', '7229', '9801', 'j', '443', 'z', 'q', 'y', '7447', '1659', '3411', '55', '5153', '9921', '2195', '1075', '8187', 'p', 'x', 'h', 'y', 't', 'a', 'r', 'f']
answer:
a, f, g, h, j, o, p, q, r, t, v, x, y, z


question:
['z', 'z', '305', 'a', 'o', '5289', '6463', '7785', 'j', '3617', '5793', '3535', 'n', '3319', '6499', 'd', '4409', '8805', '9897', '9061', 's', '6903', '1457', '2021', 'm', 'k', '7027', 'm', 'c', 'q', 'j', 'r', '6303', 's', '6271', 's', 'a', 'w', 'h', 'm', '3877', 'o', 'w', '2645']
answer:

a, c, d, h, j, k, m, n, o, q, r, s, w, z