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.geom.Point2D;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		try (Scanner sc = new Scanner(System.in)) {
			Point2D.Double P1 = new Point2D.Double(sc.nextDouble(),sc.nextDouble());
			Point2D.Double P2 = new Point2D.Double(sc.nextDouble(),sc.nextDouble());
			System.out.println(P1.distance(P2));
		}
	}
}