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:
['5761', '2289', '577', 't', '125', 'i', 'g', '9693', '747', 'd', '4829', '9587', 'f', 'k', 'w', 'v', '8607']
answer:
d, f, g, i, k, t, v, w


question:
['u', '1343', 'd', 'c', '9567', 'e', 'd', 'y', 's', '4199', '3217', '2937', '9345', 'd', 'l', '9875', '5987', 'p', '2585', '5843', '9643', '2423', 'e', 'l', 's', '3503', 'b', 'w', '9685', 'p', '6055', 'k', 'e', 'e', 't', '865', '6071', 'j', '3439', 't']
answer:
b, c, d, e, j, k, l, p, s, t, u, w, y


question:
['b', 'x', '5909', 'g', 'i', 'l', '1861', '2217', '6621', '7225', 't', '8471', '5249', '1073', '331', 'i', 'k', '9295', '4559', '9217', 'k', 'e', 'z', 'e', '7915']
answer:

b, e, g, i, k, l, t, x, z