//PROGRAM 2-2
class KelilingLingkaran {
  public static void main(String[] args) {
		
    double pi = 3.1416;
    double r = 2.12;
    double keliling;
		
    keliling = 2 * pi * r;
		
    System.out.println("Keliling lingkaran = " + keliling);
  }
}