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: ['v', 'i', 'g', 'h']

SOLUTION: -1

PROBLEM: ['t', 'p', 'u', 'a']

SOLUTION: -1

PROBLEM: ['e', 'j', '429', 'r', 'f', '17']

SOLUTION:
1, 2, 4, 7, 9