using System;

using System.Collections.Generic;

​

public class Program

{

    public abstract class Person

    {

        public string Name { get; set; }

        public int Id { get; set; }

        public abstract void PrintDetails();

    }

    class Student : Person

    {

        List<Course> Courses { get; set; } = new List<Course>();

        public void EnrollInCourse(Course course)

        {

            Courses.Add(course);

            course.AddStudent(this);

​

        }

        public override void PrintDetails()

        {

            Console.WriteLine($"Im {Name} with ID: {Id} and I'm studying at:");

            foreach (var item in Courses)

            {

                Console.WriteLine($" - {item.Name}");

            }

        }

    }

    class Course : Person

    {

        List<Student> Students { get; set; } = new List<Student>();

        public void AddStudent(Student student)

        {

            Students.Add(student);

        }

        public override void PrintDetails()

        {

            throw new NotImplementedException();

        }

    }

    class Proffessor : Person

    {

        List<Course> CoursesTaught { get; set; } = new List<Course>();

        public void AddCoursesTaught(Course course)

        {

            CoursesTaught.Add(course);

        }

        public override void PrintDetails()

        {

            Console.WriteLine($"Im {Name} with ID: {Id} and I'm teaching at:");

            foreach (var item in CoursesTaught)

            {

                Console.WriteLine($" - {item.Name}");

            }

        }

    }

    static void Main(string[] args)

    {

    }

}

​