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[] a = new double[]{sc.nextDouble(), sc.nextDouble(), sc.nextDouble(), sc.nextDouble()};
        double x = a[2] - a[0], y = a[3] - a[1];
        System.out.println(Math.sqrt(x * x + y * y));
    }
}