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: ['291', 'p', '261', 'z', '21', 'w', 't', '417']

SOLUTION: 1, 2, 4, 6, 7, 9

PROBLEM: ['239', '439']

SOLUTION: 2, 3, 4, 9

PROBLEM: ['v', 'c', '315', '159', '415', 'h', 'w', 'u', 'n', '429', 'h']

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