import java.util.Scanner;

public class App2 {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        System.out.println("Enter type on shape !");
        String shape = scan.next();
        if(shape.equals("square")){
            System.out.println("Enter side on square");
            double side = scan.nextDouble();
            double result = side * side;
            System.out.println("S = " + result);
        }else if(shape.equals("rectangle")){
            System.out.println("Enter side one on rectangle");
            double side1 = scan.nextDouble();
            System.out.println("Enter side two on rectangle");
            double side2 = scan.nextDouble();
            double result = side1 * side2;
            System.out.println(result);
        }else if(shape.equals("circle")){
            System.out.println("Enter radius ");
            double radius = scan.nextDouble();
            //double result = 3.14 * radius * radius;
            double result = Math.PI * radius * radius;
            System.out.printf("s = %.2f",result);
            System.out.println("s = " + result);
        }else if(shape.equals("triangle")){
            System.out.println("Enter a:");
            double a = scan.nextDouble();
            System.out.println("Enter b:");
            double b = scan.nextDouble();
            double r = (a * b) / 2;
            System.out.printf("%.2f",r);
        }
    }
}