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;
 
class Main {  
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        double x1 = in.nextDouble();
        double x2 = in.nextDouble();
        double y1 = in.nextDouble();
        double y2 = in.nextDouble();
 
        double distance = Math.sqrt((x1 - y1)*(x1 - y1) + (x2 - y2)*(x2 - y2));
     
        System.out.printf("%5.8f", distance);
     
    }
}