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:
['i', '4447', 'g', 'o', 'j', 'p', 'l', 'q', 'o', '8777', 'r', 'v', '961', '6083']
answer:
g, i, j, l, o, p, q, r, v


question:
['r', 's', '2471', 'n', '635', 'k', '3551', '7041', '8765', '1221', '8439', '7773', '6471', 'u', 'p', '2093', '6479', '1435', '6881', 'a', 'y', 'm', 'r', '1627', 'w', 'k', 'b', '3095', '9059', '285', 'y', 'a', 'm', 'x', '637', 'i', '3407', 'e', 'e']
answer:
a, b, e, i, k, m, n, p, r, s, u, w, x, y


question:
['365', 'g', 'u', '8285', '5163', 'g', 'd', 'p', 'b', '9123', 's', '9425', '7255', '4181', '3465', '1729', 'a', 'i', '5779', 'h', '9857', 'z']
answer:

a, b, d, g, h, i, p, s, u, z