interface Shape {
    double calculateArea();
}

class Square implements Shape {

    private double side;

    public Square(double side) {
        this.side = side;
    }

    public double calculateArea() {
        return side * side;
    }
}

class Triangle implements Shape {

    private double base;
    private double height;

    public Triangle(double base, double height) {
        this.base = base;
        this.height = height;
    }

    public double calculateArea() {
        return 0.5 * base * height;
    }
}

public class Main {

    public static void main(String[] args) {
        Shape square = new Square(5.0);
        Shape triangle = new Triangle(4.0, 6.0);

        System.out.println("Area of Square: " + square.calculateArea());
        System.out.println("Area of Triangle: " + triangle.calculateArea());
    }
}