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:
['9351', 'v', 'h', 'z', 'g', 'f', 't', 'q', 'g', 'o', '4073', 'n', '6149', '1735', '157', 'm']
answer:
f, g, h, m, n, o, q, t, v, z


question:
['2349', 'p', 'a', '435', 'y', 'h', '3249', 'o']
answer:
a, h, o, p, y


question:
['4235', 'i', '7175', '1653', 'g', 'j', '8979', 's', '5523', 's', 't', '1797', '8799', 'r', '1487', '2167', '341', 'u', '969', '2547', '1177']
answer:

g, i, j, r, s, t, u