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 x1,y1,x2,y2,x,y,s;
        x1=scan.nextDouble();
        y1=scan.nextDouble();
        x2=scan.nextDouble();
        y2=scan.nextDouble();
        x=x2-x1;
        y=y2-y1;
        s=Math.sqrt(x*x+y*y);
        System.out.println(s);
    }
}