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.*;
import java.io.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc=new Scanner(System.in);
        double x1=sc.nextDouble();
        double y1=sc.nextDouble();
        double x2=sc.nextDouble();
        double y2=sc.nextDouble();
        double dis=Math.sqrt((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1));
        System.out.println(dis);
    }
}