using System;

public class staff : service

{

public void book()

{

Console.WriteLine("Booked seat ");

} }

public class service : typeofseat

{

public void service_1_emp()

{

Console.WriteLine("Welcome passenger");

}

public void service_2_emp()

{

Console.WriteLine("Offer for seat ");

}

public void service_3_emp()

{ Console.WriteLine("Book seat");

} }

public class typeofseat: billing

{

public void seat()

{

Console.WriteLine(" Book seat for customer");

} }

public class billing

{

public void bill()

{

Console.WriteLine("Bill printed");

} }

public class Program

{

public static void Main()

{

staff s = new staff();

s.service_1_emp();

s.service_2_emp();

s.seat();

s.book();

s.bill();

}

}