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: ['q', 'p', 'y', 'p', 'k', 'r', '481', 'v']

SOLUTION: 1, 4, 8

PROBLEM: ['u', '157', '63', '411', 'x', 'c', 'k', 'z', 'i', '279', '311', '431']

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

PROBLEM: ['b', 'h', 'k', 'm']

SOLUTION:
-1