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: ['a', 'n', '423', 'y', 'y', 'u', '55', 'y', '295', '73', 't', 'p']

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

PROBLEM: ['s', '391', 'z', '67', '371', '195', '77', '373', 'g', '249', 'm']

SOLUTION: 1, 2, 3, 4, 5, 6, 7, 9

PROBLEM: ['u', '203', '445']

SOLUTION:
0, 2, 3, 4, 5