import java.util.Scanner;

public class AreaOfFigures_07 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String figure = scanner.nextLine();
        double a = Double.parseDouble(scanner.nextLine());

        double square = a * a;

        double circle = a * a* Math.PI;

        if (figure.equals("square")) {
            System.out.printf("%.3f", square);
        } if (figure.equals("rectangle")) {
 			double b = Double.parseDouble(scanner.nextLine());
        double rectangle = a * b;
            System.out.printf("%.3f", rectangle);
        }
        if (figure.equals("circle")) {
            System.out.printf("%.3f", circle);
        } if (figure.equals("triangle")) {
			 double b = Double.parseDouble(scanner.nextLine());
            double triangle = a * b / 2;
            System.out.printf("%.3f", triangle);
        }
    }
}