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) {
        // write your code here
        Scanner scanner=new Scanner(System.in);
        Double x1=scanner.nextDouble();
        Double y1=scanner.nextDouble();
        Double x2=scanner.nextDouble();
        Double y2=scanner.nextDouble();
        System.out.println(Math.sqrt(Math.pow(x1-x2,2)+Math.pow(y1-y2,2)));
    }

}