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:
['j', '8797', 'i', '5443', 'i', 'f', '7593', 'u', 'h', '3251', 'l', '681', 'y', 'n', 'r', '1699', '1379', '8987', '6955', 'x', 'p', 'x', '553', 'q', '5679', 'q', 'w', '9007', 'r', '8945', '7351', 'a', 'v', 'k', '1309', 'v', 'i', '4161', 'a', 'q', '2919', '6917', '6845']
answer:
a, f, h, i, j, k, l, n, p, q, r, u, v, w, x, y


question:
['z', 'l', 's', 'f', 'j', 'x', '1125', 'd', '37', '5009', '9187', 'b', '8683', '8841', 'y', '9955', '1571', 'm', '347', '3679', '5797', '2133', 'g', 'u', '9817', '6347', '2067', '1927', '167', '4215', '45', 't', 'd', '6599', '4751', 'g', 'l', 'u', '7881', 's']
answer:
b, d, f, g, j, l, m, s, t, u, x, y, z


question:
['3195', '3885', '8477', 'v', '5647', 'n', '389', '2515', 'j', '9343', 'j', '6143', 'v', 'm', 'k', '8865', 'w', 'f', 'w', '9099', 'j', 'h', '507', 'b', 'o', 'j', '5829', 'q']
answer:

b, f, h, j, k, m, n, o, q, v, w