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: ['q', 'u', '199', 'v', '249']

SOLUTION: 1, 2, 4, 9

PROBLEM: ['z', 'q', 'u', '383']

SOLUTION:
3, 8