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) {
		Scanner scan = new Scanner(System.in);
		
		double x1, y1, x2, y2;
		x1 = scan.nextDouble();
		y1 = scan.nextDouble();
		x2 = scan.nextDouble();
		y2 = scan.nextDouble();
		
		double d = Math.sqrt(Math.pow(x1 - x2, 2) + Math.pow(y1 - y2, 2));
		System.out.println(d);
		
		scan.close();
		
	}

}