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: ['b', 'i', '5533', 'v', '1393', 'y', '3273', '353', 'u', 't']

b, i, t, u, v, y