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', '171', 'p', '299', 'u', 'n', '421', '331', 'h', '21', 'h', 'x', '435', '327', '373']

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

PROBLEM: ['z', '209']

SOLUTION: 0, 2, 9

PROBLEM: ['e', '5', '407', 'h', '81', '459', '241', '117', 'y', '193', '327']

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