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.Scanner;
 
public class Main{
    public static void main(String[] args){
    	Scanner scan = new Scanner(System.in);
        double x = scan.nextDouble();
        double y = scan.nextDouble();
        System.out.printf("%.8f%n", Math.hypot(scan.nextDouble()-x, scan.nextDouble()-y));
    }
}