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.*;
public class Main {
    public static Scanner sc = new Scanner(System.in);
    public static void main(String[] args) throws Exception {
    	int i, j, k;
    	
    	double x1 = sc.nextDouble();
    	double y1 = sc.nextDouble();
    	double x2 = sc.nextDouble();
    	double y2 = sc.nextDouble();
    	
    	System.out.println(Math.hypot(x2 - x1, y2 - y1));
    }
}