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: ['e', 's', '153', 'e', '377', 'c', 'v', '437']

SOLUTION: 1, 3, 4, 5, 7

PROBLEM: ['477', 'a', 'n', 'r', '457', 'g', 'c']

SOLUTION:
4, 5, 7