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: ['99', 'c', 'v', '77', '295', '121', '95', 'z', 'b', 'p', 'd']
Student:
1, 2, 5, 7, 9