using System;

public class Point

{

private double x;

private double y;

public double X

{ 

   set

{

   this.x=value;

}

    get

{ 

   return this.x;

}

}

public double Y

{

   set

{

 this.y = value;

}

   get 

{

 return this.y;

}

}

//конструктор по подразбиране

public Point()

{

this.x = 0.0;

this.y = 0.0;

}

​

//конструктор с два параметъра

public Point(double a, double b)

{

this.x = a;

this.y = b;

}

//копиращ конструкор

 public Point(Point r)

    {

     this.x = r.x;

     this.y = r.y;

    }

//метод Distance

public static double Distance(Point p1 , Point p2) 

{

 double result;

 result = Math.Sqrt((Math.Pow((p2.x-p1.x), 2) + Math.Pow((p2.y-p2.y),2)));

 return result;

} 

}

class Program

{

static void Main(string[] args)

{

​

double d = double.Parse(Console.ReadLine());

double f = double.Parse(Console.ReadLine());

Point p1 = new Point(d , f);

double g = double.Parse(Console.ReadLine());

double h = double.Parse(Console.ReadLine());

Point p2 = new Point(g , h);

​

Console.WriteLine("Distance");

Console.WriteLine(Point.Distance(p1,p2));

}

}

​

​