using System;

class D
{
	static decimal[] ReadDec() => Array.ConvertAll(Console.ReadLine().Split(), decimal.Parse);
	static (decimal, decimal) Read2Dec() { var a = ReadDec(); return (a[0], a[1]); }
	static void Main() => Console.WriteLine(Solve());
	static object Solve()
	{
		var (h, r) = Read2Dec();

		return Area(h, r);
	}

	static decimal Area(decimal h, decimal r)
	{
		return 2 * (decimal)Math.PI * r * h + 2 * (decimal)Math.PI * r * r;
	}
}