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]: ['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']
[A]: a, f, h, i, j, k, l, n, p, q, r, u, v, w, x, y


[Q]: ['5337', '4877', '9443', '3445', 'u', '2571', 't', 'n', 'x', '1985', '5145', '3397', 'p', '9259', 's', 'x', 'u', 'c', 'g', 't', 'j', '829', '8273', 'e', 'j', 'r', 'x', '865', '4773', 'h', '4407', '8591']
[A]: c, e, g, h, j, n, p, r, s, t, u, x


[Q]: ['6095', '9385', '5945', '155', 'r', 'x', '7697', '6131', 'a', 'g', '93', 'f', 'p', 'a', 'f', 'c', '2357', 'h', 'b', '3529', '6159', 'n', '943', '3069', 'u', 'l', '4833', 'u']
[A]:
a, b, c, f, g, h, l, n, p, r, u, x