using System;

public class Program

{

    static double D(double x1,double y1, double x2, double y2)

    {

        double D = Math.Sqrt(Math.Pow(x1 - x2, 2) + Math.Pow(y1 - y2, 2));

        return D;

    }

    public static void Main()

    {

        Console.Write("x1, y1: ");

        double x1 = double.Parse(Console.ReadLine());double y1 = double.Parse(Console.ReadLine());Console.Write("x2, y2: ");

        double x2 = double.Parse(Console.ReadLine());double y2 = double.Parse(Console.ReadLine());Console.Write("x3, y3: ");

        double x3 = double.Parse(Console.ReadLine());double y3 = double.Parse(Console.ReadLine());Console.Write("x4, y4: ");

        double x4 = double.Parse(Console.ReadLine());double y4 = double.Parse(Console.ReadLine());

        double M = D(x1,y1,x2,y2) + D(x2,y2,x3,y3) + D(x3,y3,x4,y4) + D(x4,y4,x1,y1);

        Console.WriteLine("Moheet = {0}",M);

    }

}