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 x1, y1, x2, y2, d;
        
        x1 = sc.nextDouble();
        y1 = sc.nextDouble();
        x2 = sc.nextDouble();
        y2 = sc.nextDouble();
        
        d = (x1 - x2)*(x1 - x2) + (y1 - y2)*(y1 - y2);
        d = Math.sqrt(d);
        
        System.out.println(d);
        
    }
}