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