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,x2,y1,y2,rr;

		Scanner scan = new Scanner(System.in);
		x1 = scan.nextDouble();
		y1 = scan.nextDouble();
		x2 = scan.nextDouble();
		y2 = scan.nextDouble();

		rr = Math.pow( (x1-x2), 2) + Math.pow( (y1-y2), 2);

		System.out.printf("%.5f\n",Math.sqrt(rr) );

		scan.close();
	}
}