using System;

struct Tacka {

    public int x;

    public int y;

};

public class Program

{

    public static void Main()

    {

        Tacka A; Tacka B; double d;

        A.x=3; A.y=5; B.x=7; B.y=9;

        d=Math.Sqrt(Math.Pow(A.x-B.x,2)+Math.Pow(A.y-B.y,2));

        Console.WriteLine (d);

    }

}

​