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 x_1 = sc.nextDouble();
        double y_1 = sc.nextDouble();
        double x_2 = sc.nextDouble();
        double y_2 = sc.nextDouble();
        double d = Math.sqrt((x_2-x_1)*(x_2-x_1) + (y_2-y_1)*(y_2-y_1));
        System.out.println(d);
    }
}