https://www.acmicpc.net/problem/16486
using System;
class Program
{
static void Main() {
string s=Console.ReadLine();
int d1=int.Parse(s);
string s1=Console.ReadLine();
int d2=int.Parse(s1);
double pi=3.141592;
Console.Write(2*d1+2*pi*d2);
}
}