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: ['3', '181', 'o', '425', 'f', '391']

SOLUTION: 1, 2, 3, 4, 5, 8, 9

PROBLEM: ['t', '251', 'b', '241', 'z', '255']

SOLUTION: 1, 2, 4, 5

PROBLEM: ['23', '307', '471']

SOLUTION:
0, 1, 2, 3, 4, 7

