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 sc = new Scanner(System.in);
		double x1,y1,x2,y2,x,y;
		double r;
		x1 = sc.nextDouble();
		y1 = sc.nextDouble();
		x2 = sc.nextDouble();
		y2 = sc.nextDouble();
		x = Math.abs(x1 - x2);
		y = Math.abs(y1 - y2);
		x = x * x;
		y = y * y;
		r = Math.sqrt(x + y);
		System.out.println(r);
	}
}