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: ['n', '6805', 'w', '5269', '4791', '2663', '4581', 'q', 'f', '1513', '583', 'p', '7135', 'n', '4597', '6873', '5555', '7887', '1739', 'r', 'k', '5513', '167', '2141']
A:
f, k, n, p, q, r, w