using System;

namespace Geometrie

{ 

    public class Punct

    {

        public double x,y;

        public string nume;

        public Punct(string denumire,double a,double b)

        {

            nume= denumire;

            x=a;

            y=b;

        }

        public void Afis()

        {

            Console.WriteLine("{0} ({1},{2}) ",nume,x,y);

        }

    }

}

public class Segment

{

    Geometrie.Punct a,b;

    public Segment(string nume1,double ax,double ay,string nume2,double bx,double by)

    {

        a=new Geometrie.Punct(nume1,ax,ay);

        b= new Geometrie.Punct(nume2,bx,by);

    }

    public double Lungime()

    {

        return System.Math.Sqrt((b.x-a.x)*(b.x-a.x)+(b.y-a.y)*(b.y-a.y));

    }

}

public class Program

{

    public static void Main()

    {

        Console.WriteLine(s.Lungime());

    }

}