p13_AreaFigures

import java.util.Scanner;
import java.lang.String;

public class AreaFigures {
    public static void main(String[] args) {
        Scanner console = new Scanner(System.in);

        String figure = console.nextLine().toLowerCase();

        double area = 0;

        if(figure.equals("square")){
            double a = Double.parseDouble(console.nextLine());
            area = a * a;
        }else if(figure.equals("rectangle")){
            double a = Double.parseDouble(console.nextLine());
            double b = Double.parseDouble(console.nextLine());
            area = a * b;
        }else if(figure.equals("circle")){
            double r = Double.parseDouble(console.nextLine());
            area = Math.PI*( r * r);
        }else if(figure.equals("triangle")){
            double a = Double.parseDouble(console.nextLine());
            double h = Double.parseDouble(console.nextLine());
            area = ( a * h ) / 2;
        }

        System.out.printf("%.3f", area);
    }
}