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: ['e', 'q', '1457', 's', 'f', 'a', 't', 'h', 'p', 's', '1073', '5105', '1957', 't', '2025', '4887', 'l', '9499', 'd', '639', 'k', 'm', 'e', '7059', 'y', '5435', 'l', 'b', '4355']
Student:
a, b, d, e, f, h, k, l, m, p, q, s, t, y