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 line;		
		double x;
		double y;
		
		x=x2-x1;
		y=y2-y1;
		
		line=Math.sqrt(x*x+y*y);
		
		System.out.println(line);
		
		sc.close();
	}

}