Teacher:In this task, you are given an input list A. You need to extract and sort the unique digits used in the list in ascending order. Return -1 if there is no digit in the list.
Teacher: Now, understand the problem? Solve this instance: ['l', '41', '269', '273', '199', 'b', 't', '497', '217', 'i', 'y', 'j', '49']
Student:
1, 2, 3, 4, 6, 7, 9