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: ['u', 'r']

SOLUTION: -1

PROBLEM: ['v', '477', 'j', '339', '245', 'r', '417', 'g', '475', 'n', 'q', '171']

SOLUTION: 1, 2, 3, 4, 5, 7, 9

PROBLEM: ['m', 's', '135', 'u', '137', 'e', '315']

SOLUTION:
1, 3, 5, 7