/* public */ class Pi3 {
  public static void main(String[] args) {
    System.out.println("マチンの公式：" + pi3());
    System.out.println("Java API：" + Math.PI);
  }
  public static double pi3() {
    double piQuarter;
    piQuarter = 4.0 * Math.atan(1.0 / 5.0) - Math.atan(1.0 / 239.0);
    double pi = piQuarter * 4.0;
    return pi;
  }
}