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.io.*;
import java.util.Arrays;
import java.util.Scanner;

public class Main{
	public static void main(String[] args) throws IOException{ 
		Scanner sc = new Scanner(System.in);
		Double x1 = sc.nextDouble();
		Double y1 = sc.nextDouble();
		Double x2 = sc.nextDouble();
		Double y2 = sc.nextDouble();
		Double xl = x2 - x1;
		Double yl = y2 - y1;
		Double length = Math.sqrt( xl*xl + yl*yl);
		System.out.printf("%.5f",length);
	}
}