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;
class Main{
     public static void main(String[] args){
    	Scanner scan = new Scanner(System.in);
    	
    	double x1 = scan.nextDouble();
    	double y1 = scan.nextDouble();
    	double x2 = scan.nextDouble();
    	double y2 = scan.nextDouble();
    	
    	double num = Math.pow((x2 - x1), 2) + Math.pow((y2 - y1), 2);
    	double p = Math.sqrt(num); 
    	
    	System.out.println(String.format("%.8f", p));
     }
}