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 x_1 = sc.nextDouble();
	  double y_1 = sc.nextDouble();
	  double x_2 = sc.nextDouble();
	  double y_2 = sc.nextDouble();
	  
	  double a = Math.pow((x_1 - x_2),2);
	  double b = Math.pow((y_1 - y_2),2);
	  double c = Math.sqrt(a+b);
	 
	  System.out.println(c);
	  
	  }
}