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:
['4031', 't', 'o', 'c', 'x', '3007', '8329', '6345', '1267', '1017', 'o', 'x', 'l', '4129', 'd', '1987', '487', 'o', 'g', 'j', 'v', 'x', '3983', 'f', 'g', '5759', 'k', 'i', 'o', 'b', 'n', '683', 'j', 'o', 't', '4361', 'u']
answer:
b, c, d, f, g, i, j, k, l, n, o, t, u, v, x


question:
['l', 'g', 'd', 'p', '8163', '6643', 'o', 'p', 'm']
answer:
d, g, l, m, o, p


question:
['i', '6043', '8665', 'j', 'm', '7651', 'v', 'z', '1091', '7193', '9597', '1055', 'f', 'z']
answer:

f, i, j, m, v, z