TASK DEFINITION: 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.
PROBLEM: ['r', 'o', 'n', '219', 'a', '419', 'x', '261', 'h', 's', '373', '155', 's', '171']

SOLUTION: 1, 2, 3, 4, 5, 6, 7, 9

PROBLEM: ['q', 'p', 'y', 'p', 'k', 'r', '481', 'v']

SOLUTION: 1, 4, 8

PROBLEM: ['481', '447', 'm', 'j']

SOLUTION:
1, 4, 7, 8

