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: ['s', 'l', '4913', '6111', '3241', '5455', '6395', '7715', '1311', '683']

l, s