using System;
using System.Collections.Generic;

namespace Task_1020
{
    public class Program
    {
        private struct Point {
            public double X { get; set; }
            public double Y { get; set; }
        }
        public static void Main() {
            Point nR = Read();
            double n = nR.X;
            double r = nR.Y;

            var points = new List<Point>((int)n);
            for (int i = 0; i < n; i++) {
                points.Add(Read());
            }

            double l = 2*Math.PI*r;

            if (n == 1) {
                Console.Write(String.Format("{0:f2}", l).Replace(',', '.'));
            }
            else {
                l += ComputeLength(points[0], points[(int) (n - 1)]);

                for (int i = 0; i < n - 1; i++) {
                    l += ComputeLength(points[i], points[i + 1]);
                }
                Console.Write(String.Format("{0:f2}", l).Replace(',', '.'));
            }

        }

        private static double ComputeLength(Point p1, Point p2) {
            return Math.Sqrt(Math.Pow(p1.X - p2.X, 2)
                + Math.Pow(p1.Y - p2.Y, 2));
        }

        private static Point Read () {
            var twoNum = Console.ReadLine().Split(' ');
            twoNum[0] = twoNum[0].Replace('.', ',');
            twoNum[1] = twoNum[1].Replace('.', ',');
            return new Point {X = Double.Parse(twoNum[0]), Y = Double.Parse(twoNum[1])};
        }
    }
}

OMG man!
What a F*** code!))

What for these things are: Replace(',', '.') ????

you can read two double vals:
double[] point = Console.ReadLine().Split().Select(s=> double.Parse(s)).ToArray();
x = point[0];
y = point[1];

try it!

and hey....
what is this??? "Console.Write(String.Format("{0:f2}", l).Replace(',', '.'));"
????

write just: Console.Write("{0:F2}", l);

Here is mine template for C#
http://paste.ubuntu.com/473617/

Thanks for your replay. The problem was in this F***ing Replace.. =)