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.awt.Point;
import java.util.Scanner;

public class Main{

	static final Scanner s=new Scanner(System.in);

	public static void main(String args[]){
		System.out.printf(
				"%.5f",
				Point.distance(
						s.nextDouble(),
						s.nextDouble(),
						s.nextDouble(),
						s.nextDouble()
						)
				);
	}
}