import java.util.*;
import java.lang.Math.*;
class DistanceBwPoint
{
 public static void main(String arg[])
 {
   Scanner scan = new Scanner( System.in );
   int x1,x2,y1,y2;
   double dis;
   System.out.print("Enter X1: ");
   x1 = scan.nextInt();
   System.out.print("Enter Y1: ");
   y1 = scan.nextInt();
   System.out.print("Enter X2: ");
   x2 = scan.nextInt();
   System.out.print("Enter Y2: ");
   y2 = scan.nextInt();
   dis=Math.sqrt((x2-x1)*(x2-x1) + (y2-y1)*(y2-y1));
    System.out.println("distance between"+"("+x1+","+y1+"),"+"("+x2+","+y2+")="+dis);
 }
}