Definition: 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.
Input: ['5031', 't', 'v', '5511', '5711', '1247', '1159', 'y', 'u']

t, u, v, y