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=scan.nextDouble();
		double y1=scan.nextDouble();
		double x2=scan.nextDouble();
		double y2=scan.nextDouble();
		double d=Math.pow((x1-x2),2)+Math.pow((y1-y2),2);
		System.out.printf("%.8f\n",Math.sqrt(d));
		scan.close();
	}
}