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.*;
public class Main{
    public static void main(String[] args){
	Scanner in = new Scanner(System.in);
	double x1,x2;
	double y1,y2,result;

	x1 = in.nextDouble();
	y1 = in.nextDouble();
	x2 = in.nextDouble();
	y2 = in.nextDouble();

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