Problem: Write a program which calculates the distance between two points P1(x1, y1) and P2(x2, y2).



Input

Four real numbers x1, y1, x2 and y2 are given in a line.

Output

Print the distance in real number. The output should not contain an absolute error greater than 10-4.

Example

Input

0 0 1 1


Output

1.41421356

Solution (in JAVA):

Solution:
import java.util.*;

public class Main{
    public static void main(String[] args){
        Scanner scan=new Scanner(System.in);
        Double point1x,point1y,point2x,point2y;
        
        point1x=scan.nextDouble();
        point1y=scan.nextDouble();
        point2x=scan.nextDouble();
        point2y=scan.nextDouble();
        System.out.print(Math.hypot(point1x-point2x,point1y-point2y));
    }
}