public static List<Integer> gradingStudents(List<Integer> grades) {
        ListIterator<Integer> it = grades.listIterator();
        while(it.hasNext()){
            int grade = it.next();
            if(grade >= 38 && (5 - grade%5) < 3){
                it.remove();
                it.add(5 - grade%5 + grade);
            }
        }  
        
        return grades;
    }