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: ['181', 'n', 'p', '349', '321', '457', 'h', 's', 't', 'k', 'x', 'a', '145', '135', 'u']

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

PROBLEM: ['43', '479', '317', 'w', '475', '255', '3', 'x']

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

PROBLEM: ['r', 'i', '21', 'y']

SOLUTION:
1, 2