import java.util.*;
import java.io.*;

class TooManyWheelsException extends RuntimeException {
}

class Vehicle {
    private String name;
    private ArrayList<Wheel> wheels = new ArrayList<>();
    protected int needsWheels = 0;

    public Vehicle(String name){
        setName(name);
    }

    public void setName(String name){
        this.name = name;
    }

    public String getName(){
        return name;
    }

    public void addWheel(Wheel wheel){
        if (!hasAllWheels())
            wheels.add(wheel);
        else
            throw new TooManyWheelsException();
    }

    public boolean hasAllWheels(){
        return (wheels.size() == needsWheels);
    }

    public int getCurWheels(){
        return wheels.size();
    }

    public String toString(){
        return "Vehicle " + name + " " + needsWheels;
    }
}

class Car extends Vehicle {
    public Car(){
        super("Car");
        this.needsWheels = 4;
    }


    public String toString(){
        return "Car " + needsWheels;
    }
}

class Bicycle extends Vehicle {
    public Bicycle(){
        super("Bicycle");
        this.needsWheels = 2;
    }

    public String toString(){
        return "Bicycle " + needsWheels;
    }
}

class Wheel {
    public int diameter;
}

public class Sandbox {

    public static void main(String args[]) {
        try {
            ArrayList<Vehicle> vehicles = new ArrayList<>();
            for(int i = 0; i < 12; ++i){
                if (Math.random() < 0.3){
                    vehicles.add(new Car());
                } else if (Math.random() < 0.6){
                    vehicles.add(new Bicycle());
                } else {
                    vehicles.add(new Vehicle("unknown"));
                }

                Vehicle v = vehicles.get(i);
                //while(!v.hasAllWheels())
                while(true)
                {
                    try {
                        System.out.println(v + " currently has " + v.getCurWheels() + " wheels");
                        v.addWheel(new Wheel());
                    } catch(TooManyWheelsException tmwe){
                        break;
                    }
                }


            }
            /*
            for(int i = 0; i < vehicles.size(); ++i){
                System.out.println(vehicles.get(i));
            }
            */

        } catch(Exception e){
            e.printStackTrace();
            System.out.println("Unexpected error, sorry!");
        }
    }
}