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: ['437', 'e', 'b', 'f', '203', 't', '5', '461', 'e', '367', '391', '81']

SOLUTION: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9

PROBLEM: ['b', 'm', '471']

SOLUTION: 1, 4, 7

PROBLEM: ['g', '109', 'm', '169', '443', 'm', '57', '285', 'x', '171', '367']

SOLUTION:
0, 1, 2, 3, 4, 5, 6, 7, 8, 9