Teacher: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.
Teacher: Now, understand the problem? Solve this instance: ['1463', '3267', 'h', 'a', 'q', '7589', '3435', 'c', '6965', 'm', 'w', 'g', 'x', '9661', '4555', '87', 'o', '3725', '3873', '2779', 'r', '3525', 'g', '9605', 't', '9265']
Student:
a, c, g, h, m, o, q, r, t, w, x