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]: ['m', '5005', 'y', 'h', 'w', '3609', 'p', '2539', '3307', 'p']
[A]: h, m, p, w, y


[Q]: ['1429', '7273']
[A]: -1


[Q]: ['8705', 'z', 'd', 'p', 'n', '3817', 'k', 'k', 'c', '2095', 'u', '8005', 'i', 'v', 'e', 'u', 'y', '4787', 'n', '353', 'y', '5981', '6115', '6939', '3125', '6521', 'r', '6507']
[A]:
c, d, e, i, k, n, p, r, u, v, y, z