package Lesson3;

import java.util.Scanner;

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

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




        }
    }