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 std = new Scanner(System.in);
		double x1 = Double.parseDouble(std.next());
		double y1 = Double.parseDouble(std.next());
		double x2 = Double.parseDouble(std.next());
		double y2 = Double.parseDouble(std.next());
		double res = Math.pow(Math.pow((x1-x2),2) + Math.pow((y1-y2),2),0.5);
		System.out.println(String.format("%.5f", res));
	}
}