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

SOLUTION: -1

PROBLEM: ['k', '373', 'b', '305', 'i', 'n', 'z', 'm', 'c']

SOLUTION: 0, 3, 5, 7

PROBLEM: ['427', '499', 'a', 'v', '121', 'r']

SOLUTION:
1, 2, 4, 7, 9

