for(Character character : testInput.toCharArray()){
            if(!characterInputStack.empty() && Math.abs(character - characterInputStack.peek()) == 32){

//                if(Character.toLowerCase(character) == Character.toLowerCase(characterInputStack.peek())) {
                    System.out.println("Current character: " + character);
                    System.out.println("Stack character: " + characterInputStack.peek());
                    System.out.println("-------------------------------------------");
                    counter++;
//                }
                characterInputStack.pop();
            } else {
                characterInputStack.push(character);
            }
        }