Detailed Instructions: 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: ['2965', 'c', 'r', 'w', 'f', 'u', 'k', 'c', '4917', '7599', '3053', '9931', 'n', '3217', 'j', 'a', 'c', 't', '8927', '3771', '6533', '6231', '6711']
A:
a, c, f, j, k, n, r, t, u, w