public class ElectricityBill implements Runnable {
    private int units;
    private double bill;
    private double unitcost=2.10;
    public ElectricityBill (int units){
        this.units=units;
    }
    public void run(){
        String tname=Thread.currentThread().getName();
        System.out.println(tname +"Bill Calculation Started:");
        try{
           Thread.sleep(10);

        }
        catch(InterruptedException e){
            e.printStackTrace();
        }
        bill =units<=250?300:300+(units-250)*unitcost ;
        System.out.println("Bill Form:"+tname+" ,"+bill);
    }
    public double getBill(){
        return bill;
    }

    
}






public class MainBill {
    public static void main(String[] args) {

        ElectricityBill house1=new ElectricityBill(200);
        ElectricityBill house2=new ElectricityBill(500);
        ElectricityBill house3=new ElectricityBill(400);

        Thread t1=new Thread(house1,"house1");
        Thread t2=new Thread(house2,"house2");
        Thread t3=new Thread(house3,"house3");

        t1.start();
        t2.start();
        t3.start();

        try{
            t1.join();
            t2.join();
            t3.join();

        }catch(InterruptedException e){
            e.printStackTrace();
        }

        double TotalRevenue=house1.getBill()+house2.getBill()+house3.getBill();
        System.out.println("Total Revenue is :"+TotalRevenue);

    }
}