package com.company;

import java.util.Scanner;


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

        System.out.print("Введите радиус 1 окружности: ");
        double r1 = scan.nextInt();
        System.out.print("Введите радиус 2 окружности: ");
        double r2 = scan.nextInt();
        System.out.print("Введите радиус 3 окружности: ");
        double r3 = scan.nextInt();


        double s1 = ((r3 + r3) * (r3 + r3) - circleArea(r3));
        double s2 = (circleArea(r2) - circleArea(r1))*0.625;
        double S = s1+s2;

        System.out.println(S);
    }

    private static double circleArea(double r) {
        return Math.PI*r*r;
    }
}