interface Shape {
    void draw();
}

class Circle implements Shape {
    @Override
    public void draw() {
        System.out.println("Drawing a Circle");
    }

    public void calculateArea() {
        System.out.println("Calculating Circle Area");
    }
}

class Square implements Shape {
    @Override
    public void draw() {
        System.out.println("Drawing a Square");
    }

    public void calculateArea() {
        System.out.println("Calculating Square Area");
    }
}

public class RuntimePolymorphismExample {
    public static void main(String[] args) {
        // Creating objects of the subclasses
        Shape circle = new Circle();
        Shape square = new Square();

        // Demonstrate runtime polymorphism
        // The draw() method of the appropriate subclass will be called dynamically
        circle.draw();
        square.draw();

        // Uncommenting the lines below will result in a compilation error
        // since the calculateArea() method is not part of the Shape interface
        // circle.calculateArea();
        // square.calculateArea();

        // However, calculateArea() method can still be called if it is casted to the specific subclass
        ((Circle) circle).calculateArea();
        ((Square) square).calculateArea();
    }
}