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: ['m', 'e', 'g']

SOLUTION: -1

PROBLEM: ['395', 'p', '373']

SOLUTION: 3, 5, 7, 9

PROBLEM: ['x', '435', '107', '49', 'i', '13', '341', 'u', '373', 'k', 'u']

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