class Day implements Comparable {

    public static Set<String> getDayStringTreated(Set<Day> days, String toBeRemoved)
    {
        Set<String> result = new HashSet<>();
        for (Day day : days)
        {
            result.add(day.dayStr.replace(toBeRemoved, ""));
        }
        return result;
    }

    public  Day(String dayStr);
    public  Day(String dayStr, List<Integer> hours);

}