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 sc = new Scanner(System.in);
        double x1 = sc.nextDouble();
        double y1 = sc.nextDouble();
        double x2 = sc.nextDouble();
        double y2 = sc.nextDouble();
        double a;
        double b;

       
       a = x2 - x1 ;
       b = y2 - y1;
        double c = Math.sqrt(a * a + b * b);
        System.out.printf("%.8f",c);
    }

}