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]: ['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]: ['j', '917', 'w', 't', '8873', '1431', '8059', '7041']
[A]: j, t, w


[Q]: ['r', 'y', '4789', 'b', '5985', 't', '9945', 'c', '3981', '1863', '4223', 'k', '3211', '5021', 'g', 't']
[A]:
b, c, g, k, r, t, y