```

public class StringClassification {

    public List<String> classifyStrings(List<String> inputStrings) {

        List<String> aList = new List<String>();

        List<String> bList = new List<String>();

        for (String inputString : inputStrings) {

            if (!String.isEmpty(inputString) && Character.isLetter(inputString.charAt(0))) {

                String firstLetter = inputString.substring(0, 1).toLowerCase();

                if (firstLetter.compareTo('a') >= 0 && firstLetter.compareTo('l') <= 0) {

                    aList.add(inputString);

                } else {

                    bList.add(inputString);

                }

            }

        }

        return aList;

    }

}

```