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: ['7123', 'm', 'h', '4065', 'c', 'n', '187', '3899', 'r', 'k', '2071', '9481', '6277']
A:
c, h, k, m, n, r