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.

[Q]: ['n', '9571', '2983', '7597', 'v', 'y', '1993', '1403', '8309', '7043', 'c', '7329', 'p', '4479', 'p']
[A]: c, n, p, v, y


[Q]: ['k', '6595', '1595', 'v', 'h', 'b', '8815', '6681', 'j', '7581', 'p', '9095', '5453', 'r', 'y', '7755', 'x', '1853', 'k', 'q', 'u', 'j', 'q', '9651', 'o']
[A]: b, h, j, k, o, p, q, r, u, v, x, y


[Q]: ['r', '3201', 'h', 'a', '895', '437', '7559', '3529', '8103', 'd', 'g', 'x', '6263', '7227', '2769', '4031', 'p', '6021', 'y', '4859']
[A]:
a, d, g, h, p, r, x, y