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 a=sc.nextDouble();
	double b=sc.nextDouble();
	double c=sc.nextDouble();
	double d=sc.nextDouble();
	System.out.println(Math.sqrt(Math.pow(a-c,2)+Math.pow(b-d,2)));
	}
}