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]: ['w', '491', 'x', 'u', 'z', 'q', '5411', '7629', '8261', '8629', '1441', '5139', 's', 'm', '6463', 'u', 'z']
[A]: m, q, s, u, w, x, z


[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]: ['w', 'k', 'r', 'l', '1275', 'n', 'b', '2403', 'f']
[A]:
b, f, k, l, n, r, w