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.*;
import java.io.*;

public class Main {

	public static void main(String[] args) {
		Scanner in=new Scanner(System.in);
		PrintWriter out=new PrintWriter(System.out);
		double x1=in.nextDouble(),y1=in.nextDouble(),x2=in.nextDouble(),y2=in.nextDouble();
		out.printf("%f\n", Math.sqrt(Math.pow(x2-x1, 2)+Math.pow(y2-y1,2)));
		out.flush();
	}
}