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: ['215', '391', '251', '177']

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

PROBLEM: ['u', '341', '151', '1', '157', '211', '189']

SOLUTION: 1, 2, 3, 4, 5, 7, 8, 9

PROBLEM: ['453', 'i', 'g', '417', 'v', '77', '493', '433', 'y']

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