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: ['239', '439']

SOLUTION: 2, 3, 4, 9

PROBLEM: ['299', '371', '313', '17', 't', 'q']

SOLUTION: 1, 2, 3, 7, 9

PROBLEM: ['s', '31', '173', 'g', '375', 'x', 'c', 'l', 't', '171']

SOLUTION:
1, 3, 5, 7