using System;

​

namespace MyProg

{

    // STUDENT_ANSWER

    public class Person

    {

        public string familyName {get;set;}

        public string firstName {get;set;}

        public int age {get;set;}

        //if (age < 0) {throw new ArgumentException("Age must be positive!");}

        public Person(string familyName, string firstName, int age)

        {

            this.familyName = familyName;

            this.firstName = firstName;

            this.age = age;

        }

    }

    class Child : Person

    {

    }

​

    public class Program

    {

        public static void Main(string[] args)

        {

            //TEST CODE

            try

            {

                Person p = new Person(familyName: "Molenda", firstName: "Krzysztof", age: 18);

                Console.WriteLine(p);

            }

            catch (Exception e)

            {

                Console.WriteLine(e.Message);

            }

        }

    }

}