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{
	private static final Scanner scan = new Scanner(System.in);

	public static void main(String[] args){
		double x1 = scan.nextDouble();
		double y1 = scan.nextDouble();
		double x2 = scan.nextDouble();
		double y2 = scan.nextDouble();
		double dis = Math.sqrt(Math.pow(x2 - x1, 2) + Math.pow(y2 - y1, 2));
		System.out.printf("%f\n", dis);
	}
}