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 f = new Scanner(System.in);
        // fill in the dictionary with the initial value
        double x1 = f.nextDouble();
        double y1 = f.nextDouble();
        double x2 = f.nextDouble();
        double y2 = f.nextDouble();
        double dist = Math.sqrt(Math.pow((x2 - x1), 2)+Math.pow((y2-y1),2));
        System.out.println(dist);
    }
}