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:
['a', 'y', 'v', 'f', 'x', 'k', 'f', 'j', '6245', '6289', 'd', '6909', '8701', 'm', '3277', 'f', 'j', 'j', '9227', '8663', '5771', 'j', 'n', 'u', '7837', 's', '2539', '6363', 'g', 'a', '1009', 'v', '1483', 'x', 'i']
answer:
a, d, f, g, i, j, k, m, n, s, u, v, x, y


question:
['k', 'n']
answer:
k, n


question:
['e', 'd', 'f', '85', 'l', 'a', 'u', 'm', '3943', '4243', '4545', 'x', 'o', '7339', '6749', 'h', 'k', 'i', 'y', 'a', '1603', 'z', 'e', 'c', '9167', '3285', 't', 'z']
answer:

a, c, d, e, f, h, i, k, l, m, o, t, u, x, y, z