static void Main(string[] args)
        {
            // Create 4, or more, exercises.
            Exercise chickenMonkey = new Exercise("Chicken Monkey", "JavaScript");
            Exercise christmasTree = new Exercise("Christmas Tree", "JavaScript");
            Exercise heist         = new Exercise("The Heist", "C#");
            Exercise kennel        = new Exercise("Kennel", "React");
            Exercise flexboxFroggy = new Exercise("Flexbox Froggy", "CSS");

            // Create 3, or more, cohorts.
            Cohort c34 = new Cohort("Cohort 34");
            Cohort c35 = new Cohort("Cohort 35");
            Cohort c36 = new Cohort("Cohort 36");

            // Create 4, or more, students and assign them to one of the cohorts.
            Student bitoM = new Student("Bito", "Mann");

            c36.AssignStudent(bitoM);

            Student jamesM = new Student("James", "McClarty");

            c35.AssignStudent(jamesM);

            Student noahB = new Student("Noah", "Barfield");

            c34.AssignStudent(noahB);

            Student bobbyB = new Student("Bobby", "Brady");

            c34.AssignStudent(bobbyB);

            Student ellieA = new Student("Ellie", "Ash");

            c34.AssignStudent(ellieA);

            Student brantleyJ = new Student("Brantley", "Jones");

            c34.AssignStudent(brantleyJ);

            // Create 3, or more, instructors and assign them to one of the cohorts.
            Instructor andyC = new Instructor("Andy", "Collins");

            c34.AssignInstructor(andyC);

            Instructor adamS = new Instructor("Adam", "Sheaffer");

            c34.AssignInstructor(adamS);

            Instructor bryanN = new Instructor("Bryan", "Nilsen");

            c34.AssignInstructor(bryanN);


            // Have each instructor assign 2 exercises to each of the students.
            andyC.AssignExercise(noahB, heist);
            andyC.AssignExercise(ellieA, kennel);
            bryanN.AssignExercise(noahB, flexboxFroggy);
            bryanN.AssignExercise(bobbyB, flexboxFroggy);
            adamS.AssignExercise(bobbyB, kennel);
            adamS.AssignExercise(brantleyJ, chickenMonkey);
            adamS.AssignExercise(brantleyJ, flexboxFroggy);
            adamS.AssignExercise(brantleyJ, kennel);
            adamS.AssignExercise(brantleyJ, christmasTree);


            Console.WriteLine($"{c34.Name} Students:");
            foreach (Student student in c34.Students)
            {
                Console.WriteLine(student.FirstName);
                foreach (Exercise exercise in student.Exercises)
                {
                    Console.WriteLine($" - {exercise.Name} / ({exercise.Language})");
                }
                Console.WriteLine("");
            }

            List <Student> students = new List <Student>()
            {
                brantleyJ,
                noahB,
                ellieA,
                bobbyB,
                jamesM,
                bitoM
            };

            List <Exercise> exercises = new List <Exercise>()
            {
                chickenMonkey,
                christmasTree,
                heist,
                kennel,
                flexboxFroggy
            };

            List <Instructor> instructors = new List <Instructor> {
                andyC,
                adamS,
                bryanN
            };

            List <Cohort> cohorts = new List <Cohort> {
                c34,
                c35,
                c36
            };

            // List exercises for the JavaScript language by using the Where() LINQ method.
            var jsExercises = exercises.Where(exercise => exercise.Language == "JavaScript");

            Console.WriteLine("JS Exercises:");
            foreach (Exercise ex in jsExercises)
            {
                Console.WriteLine(ex.Name);
            }

            // List students in a particular cohort by using the Where() LINQ method.
            var c34Students = students.Where(student => student.Cohort == c34);
            // less expensive to just iterate over c34.Students

            // List instructors in a particular cohort by using the Where() LINQ method.
            var c34Instructors = instructors.Where(instructor => instructor.Cohort == c34);

            // Sort the students by their last name.
            var orderedStudents = students.OrderBy(student => student.LastName);

            // Display any students that aren't working on any exercises (Make sure one of your student instances don't have any exercises. Create a new student if you need to.)
            var boredStudents = students.Where(student => student.Exercises.Count == 0);

            // Which student is working on the most exercises? Make sure one of your students has more exercises than the others.
            var exhaustedStudent = students.OrderBy(student => student.Exercises.Count).Last();
            // alternatively
            var exhaustedStudent2 = students.OrderByDescending(student => student.Exercises.Count).First();

            // How many students in each cohort?
            Console.WriteLine("COHORT STUDENT COUNT");
            foreach (Cohort cohort in cohorts)
            {
                string studentPlural = cohort.Students.Count > 1 ? "students" : "student";
                Console.WriteLine("{0}: {1} {2}", cohort.Name, cohort.Students.Count, studentPlural);
                Console.WriteLine($"{cohort.Name}: {cohort.Students.Count} {studentPlural}");
            }
        }