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:
['m', '8127', '7519', '4543', '2809', '9855', 'n', '6241', 'w', 'w', 'q', 'w', 'p', '8599', '7819', '3817', 'm', 'q']
answer:
m, n, p, q, w


question:
['j', 'r', 'z', 'f', '1485', '2419', 't', 'd', '6023']
answer:
d, f, j, r, t, z


question:
['l', '4183', 'e', 'a', 'i', 'y', '2777', 'i', 'i', 'u', '3065', 'l', '8229', 'v', 'u', 'k', '3541', '501', '5497', 'q', '2859', 's', 'q', 'm', '8751', 'i']
answer:

a, e, i, k, l, m, q, s, u, v, y