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[]){
        Scanner in = new Scanner(System.in);
        
        double x1 = in.nextDouble(), y1 = in.nextDouble(), x2 = in.nextDouble(), y2 = in.nextDouble();

        System.out.printf("%f\n",Math.sqrt(Math.pow(x2 - x1, 2) + Math.pow(y2 - y1, 2)));
    }
}