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: ['255', 'u', 's', 'g', '445']

SOLUTION: 2, 4, 5

PROBLEM: ['487', 'x']

SOLUTION: 4, 7, 8

PROBLEM: ['s', 'w', 'm', '231', '197', '73', 'd', '205', '317']

SOLUTION:
0, 1, 2, 3, 5, 7, 9