import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		double r = sc.nextDouble();
		double h = sc.nextDouble();
		double c = 2 * 3.1415926 * r;
		double s = 3.1415926 * r * r;
		double t = c * h + s * 2;
		System.out.println(String.format("%.2f", t));
	}
}
/**************************************************************
	Problem: 1623
	User: admin
	Language: Java
	Result: Accepted
	Time:1137 ms
	Memory:40332 kb
****************************************************************/