using System;

public class Program

{

    public class Person {

        public string Name { get; set; }

    }

    public class Developer : Person {

        public string FavoriteLanguage { get; set; }

    }

    public class Cook : Person {

        public string FavoriteMeal { get; set; }

    }

    public static void Main()

    {

        var workingWith = "developer";

        //var workingWith = "cook";

        // check who we're working with

        Person person;

        if (workingWith.Equals("developer")) {

            // derive developer

            person = new Developer();

        } else if (workingWith.Equals("cook")) {

            // derive cook

            person = new Cook();

        } else {

            // base only

            person = new Person();

        }

        // set base props

        person.Name = "Denis";

        if (person is Developer developer) {

            developer.FavoriteLanguage = "C#";

        }

        else if (person is Cook cook) {

            cook.FavoriteMeal = "Trash";

        }

        Console.WriteLine(person.Name);

    }

}