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]: ['9923', 'x', '1901', 'v', '1459', '7503', '3829', '4929', 'k', 'c', '3329', '8793', 'n', 'a', '7249', 'b', 'l', 'l', 'm', 'p', 'b', 'a']
[A]: a, b, c, k, l, m, n, p, v, x


[Q]: ['8527', 'p', '4697', '8415', 'v', 'l', '2669', '2649', '4349', '4201', 'r', '7573', '2041', 'f', '8047', 'u', 'm', 'm', 'j', '5695']
[A]: f, j, l, m, p, r, u, v


[Q]: ['f', '2537', '6683', '2565', 'p', '5017', 'w', 't', '1779', 'g', '4171', '871', '5177', 'b', '5073', 'h', 'j', 'g', 'm', 'p', '6059', '7813', 'y', 't', 's', 'g']
[A]:
b, f, g, h, j, m, p, s, t, w, y