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) {
		double x1,y1,x2,y2;
		Scanner scan = new Scanner(System.in);
		x1=scan.nextDouble();
		y1=scan.nextDouble();
		x2=scan.nextDouble();
		y2=scan.nextDouble();
		System.out.println(String.format("%.8f", Math.sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2))));
	}
}