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:
['2593', '1835', '5089', 'v', '9723', 'f', '9279', '4257', '2175', '655', 'q', 's', 'v', 'j', 'm', '4471', '6419', '1685', '2793', 'x', '509', 's', '4833', '2125', 'b', '6379', '1075']
answer:
b, f, j, m, q, s, v, x


question:
['r', 'q', '3649', 't', '3941', 'z', '3729', 's', 'g', '6905', 'h', 'v', '1085', '6353', 'a', '9395', '5433', 'a', '2565', 'p', 'a', 'h', '1491', 'j', 'b', 'v', 'e']
answer:
a, b, e, g, h, j, p, q, r, s, t, v, z


question:
['8713', '5061', '8925', '7867', 'f', 'f', 'p', '5603', '4811', '1527', 'j', 'n', '8387', 'b', '6919', 'r', '1859', '3939', '1553']
answer:

b, f, j, n, p, r