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 sc = new Scanner(System.in);
      double x1 = sc.nextDouble();
      double y1 = sc.nextDouble();
      double x2 = sc.nextDouble();
      double y2 = sc.nextDouble();

      double calc = Math.sqrt((Math.pow((x2-x1) , 2) + Math.pow((y2-y1) , 2)));
      
      System.out.println(calc);
	}
}