using System;

public class Program

{

    public static void Main()

    {

        Person.Employee e = new Person.Employee();

        //e.Name = "ABC";

        //e.Age = 21;

        e.Designation = "sw";

        e.Id = 001;

        Console.WriteLine("{0}{1}", e.Designation, e.Id);

    }

}

​

public sealed class Person

{

    public string  Name {get; set;}

    public int Age {get; set;}

    public class Employee

    {

        public int Id {get; set;}

        public string Designation {get; set;}

    }

}