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: ['c', '1067', 'z', '4021', '6675', '2837', '4957', 'w', '9895', '1847', 'v', 'm']

c, m, v, w, z