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: ['p', 't', '211', 'r', '439', 'h', 'g', 'c', '299', '371']

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

PROBLEM: ['177', '323', 'q', 'e', 'x', 'p', '3', 'c', 'e', '23', 's', '407', 'l', '21', 'z']

SOLUTION: 0, 1, 2, 3, 4, 7

PROBLEM: ['r', 'x', 'p']

SOLUTION:
-1