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 scanner = new Scanner(System.in);
        double x1,y1,x2,y2;
        double d;
        x1 = scanner.nextDouble();
        y1 = scanner.nextDouble();
        x2 = scanner.nextDouble();
        y2 = scanner.nextDouble();

        x1 -= x2;
        y1 -= y2;

        d = Math.sqrt(x1*x1+y1*y1);
        System.out.println(d);
    }
}