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: ['305', '447', '125', 'c', '469', '231', 'c', '33', 'r', '69', 'p', 'b', '143']

SOLUTION: 0, 1, 2, 3, 4, 5, 6, 7, 9

PROBLEM: ['g', 't', '31', 't', 's']

SOLUTION: 1, 3

PROBLEM: ['131', 'd', 'd', '231', 'a', '143', 'o', '261', '171', 'd', 'g']

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