abstract class Vehicle {
    public abstract void run();
}

class Car extends Vehicle {
    public void run() {
        System.out.println("Car is running");
    }
}

class Bike extends Vehicle {
    public void run() {
        System.out.println("Bike is running");
    }
}

class Truck extends Vehicle {
    public void run() {
        System.out.println("Truck is running");
    }
}

class VehicleTest {
    public static void main(String[] args) {
        Vehicle[] vehicles = new Vehicle[3];
        vehicles[0] = new Car();
        vehicles[1] = new Bike();
        vehicles[2] = new Truck();
        for (Vehicle vehicle : vehicles) {
            vehicle.run();
        }
    }
}