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: ['a', '491', '477', '193', 'b', 'l', 'c']

SOLUTION: 1, 3, 4, 7, 9

PROBLEM: ['377', 'z', '421', '137', 't', 'v', 's', 'l']

SOLUTION: 1, 2, 3, 4, 7

PROBLEM: ['j', '5', 'm', '497', 'c', 'x', 'g', 'n', '41', 'w', '81']

SOLUTION:
1, 4, 5, 7, 8, 9