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: ['t', '9375', 't', 'r', 'b', '1309', 'w', '3251', '9153', '6249', '1561', 'u', '6127', 's', '6863', '3667', '5957', '953', '1697', 'd', 'x', 'o', '275', '111', '7421', '4573', 'k', '9695', 'c', 'v', 'c', 'k', '7549', '6651', '7851', 'h', '5541', '541', 'a', '6355', 'k', '6055', '5351']
Student:
a, b, c, d, h, k, o, r, s, t, u, v, w, x